Ssc-438 Structural Optimization for Conversion of Aluminum Car Ferry to Support Military Vehicle Payload

NTIS #

SSC-438

STRUCTURAL OPTIMIZATION FOR CONVERSION OF ALUMINUM CAR FERRY TO SUPPORT MILITARY VEHICLE PAYLOAD

This document has been approved For public release and sale; its Distribution is unlimited

SHIP STRUCTURE COMMITTEE 2005

SHIP STRUCTURE COMMITTEE

RADM Thomas H. Gilmour U. S. Coast Guard Assistant Commandant, Marine Safety and Environmental Protection Chairman, Ship Structure Committee

Mr. W. Thomas Packard Dr. Jack Spencer Director, Senior Vice President Survivability and Structural Integrity Group American Bureau of Shipping Naval Sea Systems Command

Mr. Joseph Byrne Mr.Gerard A. McDonald Director, Office of Ship Construction Director General, Marine Safety, Maritime Administration Safety & Security Transport Canada

Mr. Thomas Connors Dr. Neil Pegg Director of Engineering Group Leader - Structural Mechanics Military Sealift Command Defence Research & Development Canada - Atlantic

CONTRACTING OFFICER TECHNICAL REP. EXECUTIVE DIRECTOR Chao Lin / MARAD Lieutenant Eric M. Cooper Natale Nappi / NAVSEA U. S. Coast Guard Robert Sedat / USCG

SHIP STRUCTURE SUB-COMMITTEE

AMERICAN BUREAU OF SHIPPING DEFENCE RESEARCH & DEVELOPMENT ATLANTIC Mr. Glenn Ashe Dr David Stredulinsky Mr. Yung Shin Mr. John Porter Mr. Phil Rynn Mr. William Hanzalek

MARITIME ADMINISTRATION MILITARY SEALIFT COMMAND Mr. Chao Lin Mr. Joseph Bohr Mr. Carlos Setterstrom Mr. Paul Handler Mr. Richard Sonnenschein Mr. Michael W. Touma

NAVAL SEA SYSTEMS COMMAND TRANSPORT CANADA Mr. Jeffery E. Beach Mr. Jacek Dubiel Mr. Natale Nappi Jr. Mr. Allen H. Engle Mr. Charles L. Null

UNITED STATES COAST GUARD Mr. Rubin Sheinberg Mr. Robert Sedat Captain Ray Petow

Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle 5. Report Date

STRUCTURAL OPTIMIZATION FOR CONVERSION OF ALUMINUM CAR FERRY TO SUPORT MILITARY VEHICLE 6. Performing Organization Code PAYLOAD John J. McMullen Associates

7. Author(s) 8. Performing Organization Report No.

Kramer, R.K., McKesson, C. McConnell, J., Cowardin, W. SR-1437 Samuelsen, B. 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

John J. McMullen Associates Inc. 4300 King Street, Suite 400 11. Contract or Grant No. Alexandria, VA 22302

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered

Ship Structure Committee C/O US Coast Guard (G-MSE/SSC) 14. Sponsoring Agency Code 2100 Second Street, SW Washington, DC 20593 G-M 15. Supplementary Notes Sponsored by the Ship Structure Committee. Jointly funded by its member agencies

16 Abstract This project went through the typical procedures associated with developing the structural requirements/impacts for a Sealift conversion vessel: 1) Identify the payload requirements and a representative military vehicle payload for the Sealift vessel, 2) Determine the candidate vessels available for the conversion and make a final choice for the conversion study, 3) Develop a preliminary arrangement of the vehicle loadout, i.e., arrange the payload to ensure the selected ship can accommodate the vehicles, 4) Determine the structural loads, global, local and vehicle related, to accommodate the conversion, 5) Determine the structural modifications required to accommodate the new loads and 6) Develop the cost estimates to accommodate the structural modifications, including the addition of vehicle tie downs. The essence of this project was comparison of the structural requirements and resulting modifications from application of the ABS High Speed Naval Craft criteria and the DNV High Speed, Light Craft and Naval Surface Craft criteria. Comprehensive comparison of the global loads, secondary slam loads and vehicle deck loads is developed in the report along with the structural requirements to resist these loads. The report also presents a summary of the finite element analysis work that was developed to investigate the impact of the military payload on the vehicle deck structure. This was of particular interest because the nominal tire footprints for many vehicles are significantly greater than the stiffener spacing, which violates typical assumptions for the design of plate structure subjected to wheel loads. 17. Key Words 18. Distribution Statement Distribution unlimited, available through: National Technical Information Service U.S. Department of Commerce Springfield, VA 22151 Ph. (703) 487-4650 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized - iii -

CONVERSION FACTORS (Approximate conversions to metric measures)

To convert from to Function Value LENGTH inches meters divide 39.3701 inches millimeters multiply by 25.4000 feet meters divide by 3.2808 VOLUME cubic feet cubic meters divide by 35.3149 cubic inches cubic meters divide by 61,024 SECTION MODULUS inches2 feet centimeters2 meters multiply by 1.9665 inches2 feet centimeters3 multiply by 196.6448 inches3 centimeters3 multiply by 16.3871 MOMENT OF INERTIA inches2 feet2 centimeters2 meters divide by 1.6684 inches2 feet2 centimeters4 multiply by 5993.73 inches4 centimeters4 multiply by 41.623 FORCE OR MASS long tons tonne multiply by 1.0160 long tons kilograms multiply by 1016.047 pounds tonnes divide by 2204.62 pounds kilograms divide by 2.2046 pounds Newtons multiply by 4.4482 PRESSURE OR STRESS pounds/inch2 Newtons/meter2 (Pascals) multiply by 6894.757 kilo pounds/inch2 mega Newtons/meter2 multiply by 6.8947 (mega Pascals) BENDING OR TORQUE foot tons meter tonnes divide by 3.2291 foot pounds kilogram meters divide by 7.23285 foot pounds Newton meters multiply by 1.35582 ENERGY foot pounds Joules multiply by 1.355826 STRESS INTENSITY kilo pound/inch2 in√in) mega Newton MNm3/2 multiply by 1.0998 J-INTEGRAL kilo pound/inch Joules/mm2 multiply by 0.1753 kilo pound/inch kilo Joules/m2 multiply by 175.3

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Table of Contents

Page

EXECUTIVE SUMMARY ...... 1 1.0 INTRODUCTION...... 3 1.1 OBJECTIVES...... 3 1.2 BASIS FOR THE CONVERSIONS ...... 3 1.3 SEALIFT MISSION REQUIREMENTS SELECTED FOR THE CONVERSION VESSEL (SECTION 2) ...... 4 1.4 VESSEL SELECTED FOR THE CONVERSION STUDY (SECTION 3) ...... 4 1.5 PRELIMINARY VEHICLE ARRANGEMENT ON VEHICLE DECK (SECTION 4)...... 4 1.6 STRUCTURAL LOADS REQUIRED FORTHE CONVERSION (SECTION 5)...... 5 1.7 STRUCTURAL MODIFICATINS REQUIRED FOR THE CONVERSION (SECTION 6)...... 5 1.8 STRUCTURAL MODIFICATION COST ESTIMATES (SECTION 7)...... 5 1.9 CONCLUSIONS ...... 6 2.0 SEALIFT MISSION REQUIREMENTS OF CONVERSION VESSEL...... 7 2.1 INTRODUCTION ...... 7 2.1.1 Speed...... 8 2.1.2 Range ...... 9 2.1.3 Vehicle Stowage Capacity...... 9 2.2 DATA ON US ARMY & US MARINE CORPS NOTIONAL LOADS INVESTIGATED FOR THIS PROJECT...... 9 2.2.1 Background Assumptions...... 9 2.2.2 Summary of Existing High-Speed Military Vessel Characteristics ...... 10 2.2.3 Load Planning Assumptions...... 11 2.2.4 Elimination of M1A1 Tank and Aviation Assets from the Notional Load ....12 2.2.4.1 Elimination of M1A1 Tank Assets...... 12 2.2.4.2 Elimination of Aviation Assets ...... 12 2.2.5 Deck Height Profiles & Notes ...... 12 2.2.6 Load Planning Notes...... 14 2.2.7 Key Design Vehicle Lists ...... 15 2.2.8 Notional Load List...... 15 2.3 CONCLUSION ON SEALIFT MISSION REQUIREMENTS ...... 16 3.0 CONVERSION VESSEL CANDIDATES & THE FINAL SELECTION ...... 17 3.1 SELECTION PROCEDURES AND REQUIREMENTS...... 17 3.1.1 Required Vessel Characteristics ...... 17 3.1.2 Payload Characteristics...... 18

3.1.3 Vessel Engineering Characteristics ...... 19 3.1.4 Project Data Availability Characteristics...... 21 3.2 MENU OF CANDIDATE VESSELS ...... 22 3.3 ALIGNMENT OF CANDIDATE VESSELS AGAINST REQUIREMENTS...... 25 3.4 VESSEL DOWNSELECTION...... 28 3.5 DETAILS OF SELECTED VESSEL...... 31 3.5.1 General Specifications...... 31 3.5.2 Structural...... 32 3.5.3 Accommodation...... 33 3.5.4 Ship Control Systems ...... 35 3.5.5 Stabilisation Systems...... 35 3.5.6 Anchoring, Towing and Berthing...... 35 3.5.7 Fire Safety...... 36 3.5.8 Life-saving Appliances and Arrangements ...... 37 3.5.9 Machinery...... 37 3.5.10 Auxiliary Systems and Ship Services...... 38 3.5.11 Remote Control, Alarm and Safety Systems ...... 39 3.5.12 Electrical Installations...... 40 3.5.13 Navigational Equipment ...... 41 3.5.14 Radio Communications...... 42 3.5.15 Wheelhouse Arrangement ...... 42 3.5.16 Services...... 43 3.5.17 Manuals/Drawings...... 43 3.6 CONCLUSION...... 43 4.0 PRELIMINARY VEHICLE ARRANGEMENT OF MEU LOADOUT ...... 45 5.0 STRUCTURAL LOADS REQUIRED FOR THE CONVERSION...... 49 5.1 BACKGROUND ...... 49 5.2 ABS & DNV RULES FOR HIGH-SPEED VESSEL DEFINITION ...... 50 5.2.1 Definitions – ABS & DNV High Speed Craft...... 50 5.2.2 ABS High Speed Naval Craft...... 50 5.2.3 DNV High Speed, Light Craft...... 51 5.3 ABS STRUCTURAL LOADS...... 52 5.3.1 Use of the ABS Coastal Naval Craft Notation for R1 Equivalency ...... 53 5.3.2 ABS Global Loads...... 53 5.3.3 ABS Secondary Slam Loads...... 56 5.4 DNV STRUCTURAL LOADS ...... 63 5.4.1 DNV Service Restrictions and Vessel Types ...... 63 5.4.2 DNV Global Loads...... 68 5.4.3 DNV Secondary Slamming Loads...... 73 5.4.4 Direct Comparison of ABS and DNV Hull Girder and Secondary Slam Loads...... 78 5.5 LOADS USED FOR THE DESIGN OF THE ORIGINAL PACIFICAT ...... 81

5.6 LOADS DUE TO PAYLOAD OF MILITARY VEHICLES ...... 84 5.6.1 Investigation of Tire Footprints on Deck Structure...... 85 5.6.2 Vehicle Data – Tire Footprints ...... 86 5.6.3 Deck Structure Required – ABS HSNC Rules...... 90 5.6.4 Boundary Conditions - Discussion on the ABS Plate Thickness Requirements & Loading Conditions in the Current Conversion ...... 93 5.6.5 Continuous Span Beams with Various Load Scenarios ...... 95 5.6.6 ABS Aluminum Extrusion Properties for 6061-T6...... 98 5.6.7 Loads in Way of the Light Armored Vehicles (LAV) & Required Deck Plate ...... 98 5.6.8 Other Vehicle Deck Plate Requirements IAW ABS HSNC Rule ...... 100 5.6.8.1 Armored Combat Excavator...... 100 5.6.8.2 MK-48 LVS, Front Power Unit...... 101 5.6.8.3 Trailer, Cargo 3/4 T (M101A1)...... 102 5.6.9 Vehicle Deck Longitudinal IAW ABS...... 102 5.6.10 Vehicle Deck Structure – DNV HSLC and Naval Vessel Rules...... 106 5.6.10.1 Vehicle Deck Plating – DNV Criteria...... 106 5.6.10.2 Trailer, Cargo 3/4 T (M101A1)...... 108 5.6.10.3 Vehicle Deck Plate – Light Armored Vehicle ...... 109 5.6.10.4 Vehicle Deck Plate - MK-48 LVS, Front Power Unit ...... 110 5.6.11 Vehicle Deck Stiffening – DNV Criteria...... 112 5.6.12 Vehicle Tie-Down Loads...... 116 5.7 CONCLUSIONS TO STRUCTURAL LOADS REQUIRED FOR CONVERSION...... 116 6.0 STRUCTURAL MODIFICATIONS REQUIRED FOR CONVERSION...... 117 6.1 INTRODUCTION ...... 117 6.2 HULL GIRDER PROPERTIES & REQUIRED STRUCTURE...... 117 6.2.1 Hull Girder Stresses in the Original R4 Design...... 119 6.2.2 ABS and DNV Buckling Criteria ...... 120 6.2.2.1 ABS Buckling Criteria ...... 121 6.2.2.2 DNV Buckling Criteria...... 123 6.2.3 Hull Girder Subjected to ABS Conversion Design Primary Loads...... 125 6.2.3.1 ABS Vertical Bending Moment ...... 126 6.2.3.2 ABS Minimum Hull Girder Requirements ...... 126 6.2.3.3 ABS Transverse Bending Moment ...... 126 6.2.4 Hull Girder Subjected to DNV Conversion Design Primary Loads...... 127 6.2.5 DNV Transverse Bending Moment...... 128 6.2.6 Global Loads – Torsional and Pitch Connecting Moments...... 128 6.3 STRUCTURAL MODIFICATIONS FROM SECONDARY SLAM LOADS ...... 129 6.3.1 Slam Loads Used for Calculations ...... 131 6.3.2 ABS Structure to Resist Slam Loads...... 133 6.3.2.1 ABS Plating to Resist Slam Loads...... 133 6.3.2.2 ABS Stiffener Requirements to Satisfy Slam Loads...... 135 6.3.2.3 ABS Structure Required to Satisfy Slam Load Criteria...... 137

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6.3.2.4 Weight Estimate of ABS Structural Modifications for Slam Loading...... 137 6.3.3 DNV Structure to Resist Slam Loads ...... 138 6.3.3.1 DNV Plating to Resist Slam Loads ...... 138 6.3.3.2 DNV Stiffener Requirements to Satisfy Slam Loads...... 141 6.3.3.3 DNV Structure Required to Satisfy Slam Load Criteria ...... 143 6.3.3.4 Increased Hull Girder Properties as a Result of New Slam Load Structure ...... 143 6.3.3.5 Weight Estimate of DNV Structural Modifications for Slam Loading...... 144 6.4 VEHICLE DECK STRUCTURE & FINITE ELEMENT ANALYSIS...... 145 6.4.1 Transverse Vehicle/Tire Orientation...... 148 6.4.2 Structural & Material Properties of the Main Vehicle Deck Extrusions...... 148 6.4.3 Summary of the Finite Element Models...... 150 6.4.4 Fabrication of Main Vehicle Deck and Transverse Floors...... 151 6.4.5 Summary of Vehicle Deck FEA Results ...... 153 6.4.5.1 Discussion of Results of Analysis on ABS and DNV Loads on Heavy and Light Extrusions...... 159 6.4.5.2 Simple Support & Fixed Boundary Conditions ...... 159 6.4.6 Structural Optimization Using the ABS Mk 48 Load ...... 162 6.4.7 Verification of the Finite Element Results ...... 163 6.5 DRAWINGS FOR STRUCTURAL MODIFICATIONS ...... 164 6.6 VEHICLE DECK TIE DOWNS ...... 171 6.6.1 Arrangement of Vehicle Tiedowns...... 171 6.6.2 Installation of Vehicle Tiedowns...... 174 6.6.3 Bolting Requirements for the Tiedowns...... 175 6.6.3.1 Size of Tiedown Bolts ...... 175 6.6.3.2 Pull-Through Stresses on Vehicle Deck Plate...... 177 6.6.4 Vehicle Lashing Requirements...... 177 6.7 IMPACT ON RANGE, SPEED AND ENDURANCE FROM CONVERSION.....179 6.8 FATIGUE ANALYSIS ...... 181 6.9 CONCLUSIONS REGARDING STRUCTURAL MODIFICATIONS...... 182 7.0 STRUCTURAL MODIFICATION COST ESTIMATES...... 183 7.1 CONCLUSION...... 183 8.0 CONCLUSIONS ON REQUIRED ABS AND DNV STRUCTURAL MODIFICATIONS ...... 199 9.0 REFERENCES...... 200 10.0 DRAWING REFERENCS ...... 200 APPENDIX A. COMPREHENSIVE LOAD LISTS...... A-1 APPENDIX B. DETAILS OF CANDIDATE VESSELS ...... B-1 APPENDIX C. VEHICLE FOOTPRINT DATA...... C-1

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List of Figures

Page Figure 3-1. DWT Tonnage and Vehicle Deck Space for Candidate Vessels ...... 23 Figure 3-2. Speed, Range and Payload Performance for Candidate Vessels...... 27 Figure 4-1. Preliminary Notional Loadout for MEU on Main Vehicle Deck of PacifiCat ...... 46 Figure 5-1 ABS Classification Type from ABS 1-1-3/Table B...... 52

Figure 5-2. Design Significant Wave Heights, h1/3, and Speeds, V from ABS 3-2-1/Table 1...... 56

Figure 5-3. ABS Vertical Acceleration Distribution Factor KV, from ABS 3-2-2/Figure 7...... 57

Figure 5-4. ABS Wet Deck Pressure Distribution Factor FI, from ABS 3-2-2/Figure 9...... 58 Figure 5-5. DNV Service Restrictions from DNV 1-1-2/401...... 64 Figure 5-6. DNV Patrol & Naval Craft Notations from DNV 0-5-1...... 65

Figure 5-7. DNV Acceleration factor fg for Naval Surface Craft from DNV 5-7-3/A201...... 66

Figure 5-8. DNV Acceleration factor fg for Other Service Types from DNV 3-1-2 B/201 ...... 67 Figure 5-9. Typical Tire Footprint for Vehicle Deck Loading Data...... 84 Figure 5-10. Schematic Representation of Heavy & Light Deck Extrusions...... 85 Figure 5-11. Aspect Ratio Data for Design of Wheel Loaded Deck Plate from ABS 3-2- 3/Figure 1 ...... 90 Figure 5-12. ABS Allowable Design Stress for Wheel Loaded Decks from ABS 3-2-3/Table 2...... 91

Figure 5-13. ABS Vertical Acceleration Distribution Factor KV, from ABS 3-2-2/Figure 7...... 92 Figure 5-14. Relationship of Tire Footprint Width to Stiffener Spacing...... 95 Figure 5-15. Load, Shear & Moment Diagrams for Continuous Span Beam – One Span Loaded...... 96 Figure 5-16. Load, Shear & Moment Diagrams for Continuous Span Beam – Two Adjacent Spans Loaded ...... 97 Figure 5-17. Schematic Diagram of LAV Wheel Load on Heavy Extrusion...... 99 Figure 5-18. Various Configurations of the Light Armored Vehicle, LAV ...... 100 Figure 5-19. Deck Longitudinal Loading Diagram for ABS Calculations...... 103 Figure 6-1. DNV Torsional & Pitch Connecting Moments from DNV 3-1-3/B300...... 128 Figure 6-2. Key Plan for Stiffener Locations Subjected to Slam Loads...... 131 Figure 6-3. Tire Footprint Schematic for Plate Design on Vehicle Deck...... 145 Figure 6-4. Tire Footprint Schematic for Stiffener Design on Vehicle Deck...... 146 Figure 6-5. New Military Vehicle Arrangements with Transverse Floor Locations...... 147

Figure 6-6. Finite Element Model Used for Light Extrusion...... 150 Figure 6-7. Finite Element Model Used for Heavy Extrusion...... 151 Figure 6-8. Midship Section of PacifiCat ...... 152 Figure 6-9. Midship Section Details IWO Main Vehicle Deck Fabrication...... 153 Figure 6-10. Mk 48 Applied Load and Plate Bending Stresses on Light Extrusion...... 157 Figure 6-11. 353 Chassis Applied Load and Plate Bending Stresses on Light Extrusion...... 157 Figure 6-12. Mk 48 Applied Load and Plate Bending Stresses on Heavy Extrusion...... 158 Figure 6-13. 353 Chassis Applied Load and Plate Bending Stresses on Heavy Extrusion ...... 158 Figure 6-14. Plate Bending Stress vs. Plate Thickness...... 162 Figure 6-15. ABS Structural Modifications – Forward Portion of Side Shell...... 165 Figure 6-16. ABS Structural Modifications – Aft Portion of Side Shell...... 166 Figure 6-17 ABS Structural Modifications – Forward Portion of Bottom Hull...... 167 Figure 6-18 ABS Structural Modifications – Aft Portion of Bottom Hull ...... 168 Figure 6-19. DNV Structural Modifications – Forward Portion of Bottom Hull ...... 169 Figure 6-20. DNV Structural Modifications – Aft Portion of Bottom Hull ...... 170 Figure 6-21. Typical Cloverleaf Tiedown Shown on HSV-X1 (With Original Tiedown Tube) ...... 171 Figure 6-22. Typical Flush Cloverleaf Tiedown Fittings ...... 172 Figure 6-23. Detail of Vehicle Tiedown Installation Proposed for PacifiCat...... 175 Figure 6-24. Estimate of PacifiCat Speed – Power...... 179 Figure 6-25. PacifiCat Range vs. Speed for Varying Fuel Loads...... 180 Figure 6-26. Fuel Load vs. Speed – 4000 Nautical Mile Transit...... 180

List of Tables

Page Table 2-1. Notional Vehicle Load for Conversion Vessel...... 8 Table 2-2. Summary of Existing Sealift Mission High-Speed Vessels ...... 11 Table 2-3. Summary of Number of Sorties and Weight Requirements Based on TSV ORD ...... 11 Table 2-4. Summary of Deck Height/Area Requirements for SBCT &MEU ...... 13 Table 2-5. Summary of Deck Height/Load Requirements for SBCT & MEU...... 13 Table 2-6. Average Deck Loads/Height for SBCT & MEU...... 14 Table 2-7. Heaviest Individual Average Vehicle Load for SBCT & MEU...... 14 Table 2-8. Key Design Vehicle List for US Army (SBCT)...... 15 Table 2-9. Key Design Vehicle List for USMC (MEU)...... 15 Table 2-10. Summary of Area and Weight Requirements Based on Deck Height for the Notional Load...... 16 Table 3-1. Conversion of Notional Vehicle Load into Lane-Meters and Metric Tonnes...... 19 Table 3-2. List of Candidate Vessels and Key Characteristics. (Values in blue are estimated – Values in black are provided by builder) ...... 24 Table 3-3. Estimated Fuel Weight and Range for short listed vessels...... 26 Table 3-4. Availability of Structural Drawings For Listed Vessels...... 28 Table 4-1. Notional Vehicle Load for Conversion Vessel...... 47 Table 5-1. ABS Global Hull Girder Loads for Naval & Coastal Naval Notations – Metric Units ...... 55 Table 5-2. ABS Global Hull Girder Loads for Naval & Coastal Naval Notations – English Units ...... 55 Table 5-3. Correlation of Table Locations & Ship Frames ...... 58 Table 5-4. ABS Secondary Slam Load Pressures for Naval Craft Operational & Survival Conditions - Metric Units...... 59 Table 5-5. ABS Secondary Slam Load Pressures for Coastal Naval Craft Operational & Survival Conditions - Metric Units ...... 60 Table 5-6. ABS Secondary Slam Load Pressures for Naval Craft Operational & Survival Conditions - English Units ...... 61 Table 5-7. ABS Secondary Slam Load Pressures for Coastal Naval Craft Operational & Survival Conditions - English Units...... 62 Table 5-8. DNV Global Hull Girder Loads for R1 & Unrestricted Notations - Metric Units...... 71 Table 5-9. DNV Global Hull Girder Loads for R1 & Unrestricted Notations - English Units ....72

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Table 5-10. DNV Secondary Slam Load Pressures for R1 Notation Operational & Survival Conditions - Metric Units...... 74 Table 5-11. DNV Secondary Slam Load Pressures for Unrestricted Notation Operational & Survival Conditions - Metric Units ...... 75 Table 5-12. DNV Secondary Slam Load Pressures for R1 Notation Operational & Survival Conditions - English Units ...... 76 Table 5-13. DNV Secondary Slam Load Pressures for Unrestricted Notation Operational & Survival Conditions - English Units...... 77 Table 5-14. Comparison of ABS & DNV Global Hull Girder Loads - Metric Units...... 79 Table 5-15. ABS Secondary Slam Load Pressures for Naval Craft Operational & Survival Conditions - Metric Units...... 80 Table 5-16. DNV Secondary Slam Load Pressures for Unrestricted Notation Operational & Survival Conditions - Metric Units ...... 80 Table 5-17. DNV Rule Book Global Hull Girder Loads for PacifiCat R4 Notation - Metric Units ...... 82 Table 5-18. DNV Rule Book Secondary Slam Load Pressures for PacifiCat R4 Notation...... 82 Table 5-19. DNV Rule Book Global Hull Girder Loads for PacifiCat R4 Notation - English Units ...... 83 Table 5-20. DNV Rule Book Secondary Slam Load Pressures for PacifiCat R4 Notation...... 83 Table 5-21. Notional Vehicle Load for Conversion Vessel...... 87 Table 5-22. Vehicle Footprint Data used for Deck Structural Requirements (High Confidence) ...... 88 Table 5-23. Vehicle Footprint Data (Low Confidence – Potential Design Governing) ...... 89 Table 5-24. Vehicle Footprint Data (Low Confidence – Non-Design Governing) ...... 89 Table 5-25. Vehicle Deck Longitudinal Stiffener Shear & Moment Loads – ABS Design – English Units...... 105 Table 5-26. Comparison of ABS & DNV Vehicle Deck Plate Requirements...... 111 Table 5-27. Vehicle Data & Load Calculation for DNV Stiffeners ...... 113 Table 5-28. Vehicle Deck Longitudinal Stiffener Section Modulus Requirements – DNV Design – METRIC UNITS...... 114 Table 5-29. Comparison of ABS & DNV Vehicle Deck Section Modulus Requirements – Static 1g Loading ...... 115 Table 5-30. Comparison of ABS & DNV Vehicle Deck Section Modulus Requirements with Respective Design Accelerations...... 115 Table 5-31. Comparison of ABS & DNV Allowable Stresses for Plate & Stiffener Design.....116 Table 6-1. PacifiCat Hull Girder Properties to Resist Vertical Bending at Midship...... 118

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Table 6-2. PacifiCat Hull Girder Properties to Resist Transverse Bending ...... 118 Table 6-3. Summary of Global Loads Required for Original Design and Conversions...... 118 Table 6-4. Information Extracted from DNV 3.3.2/Table B4 ...... 119 Table 6-5. ABS Material Properties for Primary Bending – Metric Units ...... 125 Table 6-6. ABS Material Properties for Primary Bending – English Units...... 125 Table 6-7. ABS & DNV Hull Girder Allowable Stresses - Primary Bending...... 126 Table 6-8. ABS Minimum Hull Girder Requirements for Vertical Bending ...... 126 Table 6-9. Secondary Stiffeners Subjected to Slam Load ...... 130 Table 6-10. ABS Slam Loads for Naval Craft Operational & Survival Conditions...... 132 Table 6-11. DNV Slam Loads for Unrestricted Operational & Survival Conditions...... 132 Table 6-12. DNV Secondary Slam Load Pressures for R4 Notation...... 133 Table 6-13. ABS Naval Craft Operational Slam Loads – New Hull Plating Requirements & Existing Thicknesses...... 134 Table 6-14. Summary of ABS Allowable Secondary Bending Stresses ...... 135 Table 6-15. ABS Naval Craft Operational Slam Loads– Section Modulus Requirements & Existing Strength...... 136 Table 6-16. ABS Naval Craft Operational Slam Loads– Inertia Requirements & Existing Strength ...... 136 Table 6-17. Weight Increase to Accommodate ABS Structural Modifications – Open- Ocean, Unrestricted...... 138 Table 6-18. DNV Unrestricted Operation Slam Loads– New Hull Plating Requirements & Existing Thicknesses...... 140 Table 6-19. Summary of DNV Allowable Secondary Bending Stresses...... 141 Table 6-20. DNV Unrestricted Operation Slam Loads– Section Modulus Requirements & Existing Strength...... 142 Table 6-21. DNV Unrestricted Operation Slam Loads– Shear Area Requirements & Existing Strength...... 142 Table 6-22. Hull Girder Properties with Revised DNV Slam Required Scantlings ...... 143 Table 6-23. Weight Increase to Accommodate DNV Structural Modifications – Open- Ocean, Unrestricted...... 144 Table 6-24. ABS & DNV Allowable Stresses for Vehicle Deck Structure...... 149 Table 6-25. Mechanical Properties - Heavy & Light Extrusions on Vehicle Deck...... 149 Table 6-26. ABS Load, Light Extrusion, Tire Centered on Plate...... 155 Table 6-27. ABS Load, Light Extrusion, Tire Centered on Stiffener...... 155 Table 6-28. ABS Load, Heavy Extrusion, Tire Centered on Plate...... 155

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Table 6-29. ABS Load, Heavy Extrusion, Tire Centered on Stiffener...... 155 Table 6-30. DNV Load, Light Extrusion, Tire Centered on Plate...... 156 Table 6-31. DNV Load, Light Extrusion, Tire Centered on Stiffener...... 156 Table 6-32. DNV Load, Heavy Extrusion, Tire Centered on Plate ...... 156 Table 6-33. DNV Load, Heavy Extrusion, Tire Centered on Stiffener ...... 156 Table 6-34. Plate Bending Stress Coefficients From Roark & Young...... 160 Table 6-35. ABS Plate Bending Stress @ Center & Edge of Light Extrusion (FEA Based).....161 Table 6-36. ABS Plate Bending Stress @ Center & Edge of Heavy Extrusion (FEA Based) ...161 Table 6-37. FEA Results vs. Roark Predictions ...... 164 Table 6-38. Vehicle Lashing Requirements, US Marines ...... 173 Table 6-39. Tiedown Requirements for the Conversion...... 173 Table 6-40. Grade 5 Bolts Required for Tiedowns...... 176 Table 6-41 Weight of Vehicle Lashing Hardware...... 178

LIST OF ABBREVIATIONS AND SYMBOLS

This document presents two List Of Symbols pages, one for ABS and one for DNV.

LIST OF SYMBOLS – ABS High Speed Naval Craft Rules

B Beam of Vessel, meters

Bcl Distance between hull centerlines in a catamaran, meters

Bw Maximum waterline beam, meters

Bwl Waterline breadth, meters

Cb Block coefficient

C1, C2 & C3 ABS Design coefficients

FD ABS design area factor

FI ABS Wet Deck pressure distribution factor

fp ABS Design Stress

ha Vertical distance from lightest draft waterline to underside of Wet Deck, meters

h1/3 Significant wave height, meters L Length of Vessel, meters

ls ABS length of slam load

KV ABS Vertical Acceleration distribution factor

K1, K2 ABS Design coefficients

k1 & k2 ABS Design coefficients

Msl ABS Slam Induced Bending Moment

Mswh ABS Still Water Hogging Moment

Msws ABS Still Water Sagging Moment

Mth ABS Transverse Bending Moment

Mtt ABS Torsional Moment

Mwh ABS Wave Induced Hogging Moment

Mws ABS Wave Induced Sagging Moment

Nh Number of hulls in a multi-hulled vessel

N1, N2, N3 ABS design coefficients

ncg Vertical Acceleration at the center of gravity of the vessel

nxx Vertical acceleration at section x-x of the vessel

pbxx Bottom design slamming pressure at any section clear of LCG

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psxx Side and transom slamming pressure V Speed of Vessel, knots

VI Relative impact velocity W ABS static wheel load β Coefficient based on aspect ratio of deck plating panel

βbx Deadrise angle at any section clear of the LCG, degrees

βcg Deadrise at Longitudinal Center of Gravity, degrees ∆ Displacement of Vessel, metric tones, kilograms

σa ABS allowable stress for design of deck plate subjected to wheel loads

σy Yield stress of material τ Running trim at V, degrees

LIST OF SYMBOLS – DNV High Speed, Light Craft & Naval Vessel Rules

A Design area for element to be designed for slamming calculations

AR Reference area for slamming calculations, crest/hollow landing calculations a Tire footprint dimension parallel to deck stiffening 2 acg DNV Vertical design acceleration at craft’s center of gravity, m/s av Vertical design acceleration for wheel load calculations

a0 DNV Acceleration parameter B Beam of Vessel, meters

BMAX Maximum width of submerged portion of hulls – sum of both hulls for twin hull craft

Btn Breadth of cross structure, meters

BWL Maximum width of waterline – sum of both hulls for twin hull craft b Transverse distance between the centerline of the two hulls in twin hull craft. Also, Tire footprint dimension perpendicular to deck stiffening

bs Breadth of slamming reference area

CB Block coefficient

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CH Correction factor for height above waterline, slam pressure calculation

CL Correction factor for length of craft, slam pressure calculation

CW Wave coefficient c Coefficient used in design of deck structure subjected to wheel loads d Coefficient used in design of deck stiffening subjected to wheel loads

er Mean distance from the center of AR/2 end areas to the vessels LCG

ew One Half of the distance form the LCG of the fore half body to the LCG of the aft half body = 0.25L if not known (0.2L for hollow landing)

Fy Horizontal split force on immersed hull, transverse bending calculation

fg DNV Acceleration factor

f1 Allowable stress reduction factor 2 g0 Acceleration due to gravity, 9.81 m/s

HC Minimum vertical distance from waterline to load point in questions, wet deck slam pressure calculation

HL Necessary vertical clearance from waterline to load point to avoid slamming, wet deck slam pressure calculation

HS Significant wave height

HS MAX Maximum significant wave height in which the vessel is allowed to operate

H1 Design coefficient for vertical bending moment calculation k Design coefficient for crest/hollow landing calculations

ka, kb Coefficients for bottom slamming pressure calculation

ka Coefficient is also used to determine vehicle deck plate thickness requirement

kc Hull type clearance factor, wet deck slamming pressure calculation

kl Longitudinal distribution factor for slam pressure calculations

kt Longitudinal pressure distribution factor, wet deck slamming pressure calculation

kw Coefficient for vehicle deck plate thickness

k1, k2, k3 DNV design coefficients

xviii

kz Coefficient used for deck stiffening design subjected to wheel loads L Length of Vessel, meters

LBMAX Length where BMAX/BWL > 1 l Length of stiffener subjected to wheel load

ls Longitudinal extent of slamming reference area

MB DNV Crest and Hollow Landing hull girder bending moments

Mp DNV Hull girder Pitch Connecting moment

Ms DNV Transverse hull girder bending moment

Mso DNV Transverse still water bending moment

Msw DNV Still water bending moment

Mt DNV Torsional hull girder moment

Mtot hog DNV Total longitudinal hogging moment acting on the hull girder

Mtot sag DNV Total longitudinal sagging moment acting on the hull girder m Coefficient used for deck stiffening design subjected to wheel loads n Number of hulls in slamming calculation n0 Number of tires on an axle for wheel load calculations p Design pressure in way of tire footprint loads

psl DNV variable used to describe various slamming pressures; bottom, Wet Deck, forebody side and bow Q Maximum axle load RX DNV Service Restriction Notation where X can vary from 0 to 6 r Rigidity factor for design of deck stiffening subjected to wheel loads s Stiffener spacing T Draft of vessel

TL Draft at lowest service speed

T0 Draft at L/2 at normal operating condition and speed V Speed of Vessel, knots x Distance from AP to position considered Z Section Modulus required for deck stiffening in way of vehicle footprint loads z Height from baseline to wet deck

xix

α Flare angle β Coefficient based on aspect ratio of deck plating panel

βx Deadrise angle at section under consideration

βcg Deadrise angle at LCG ∆ Displacement of Vessel, metric tonnes, kilograms γ Angle between the waterline and a longitudinal line at point considered, slam calculation ρ Liquid density σ Reduced allowable stress after consideration of function of structural element being designed

σ0 Allowable stress before application of reduction factor τ Running trim at V, degrees

EXECUTIVE SUMMARY

This report provides a comparison of the structural modifications resulting from the application of the ABS High Speed Naval Craft criteria and the DNV High Speed, Light Craft and Naval Surface Craft criteria to a ferry conversion. The British Columbia PacifiCat ferry was chosen as the conversion vessel to accommodate the military vehicle payload selected for the project, a portion of the USMC Marine Expeditionary Unit, MEU. The US Army Stryker Brigade Combat Team was also considered as a candidate loadout for the conversion.

In order to satisfy the conversion requirements it was necessary that the converted vessel be able to operate in the open-ocean, unrestricted environment. The original design of the PacifiCat ferries was developed in accordance with the criteria of the DNV R4 service area restrictions. This is defined by DNV as an Inshore condition, which requires that a ship be no more than 5 nautical miles from safe harbor during Winter operations, 10 nautical miles during Summer operations and 20 nautical miles in a Tropical environment, significantly different from the open-ocean criteria required for the converted vessel.

The results of the study indicate that neither ABS nor DNV would require any structural modifications to accommodate global hull girder loads or vehicle deck loads resulting from the MEU. Application of the ABS rules would result in just over 2 metric tonnes of structural modifications to accommodate secondary slam loads whereas the DNV rules require an additional 30 metric tonnes of structure to accommodate the slam loads.

The study also includes the required modifications to the vehicle deck to accommodate vehicle tiedowns, which are considered separate from the loading criteria mentioned above. There are no differences between ABS and DNV accommodating the tiedowns but their procurement and installation costs are included as part of the estimate for both ABS and DNV.

Cost estimates provided at the end of the report compare the structural modifications for ABS and DNV. The cost estimates include the vehicle tie downs and port facility costs as well as structural modifications resulting from application of the rules.

1.0 INTRODUCTION

This project was performed under Solicitation Number DTMA1R03004 for the Department of Transportation/Maritime Administration.

1.1 OBJECTIVES

As stated in the Solicitation, there were three Objectives to be served by this project:

1. Develop the detail design of an existing large aluminum car ferry to increase its structure to handle military vehicles for unrestricted, open-ocean service. 2. Demonstrate the required changes and impacts to ship structure to accommodate the military payload. 3. Allow commercial designers to consider this aspect of a functional design in their studies to minimize conversion requirements and allow possible USN service to augment high-speed Sealift capability.

This report directly addresses the first two objectives and provides valuable insight for commercial designers to consider the inclusion of military vehicle payloads and unrestricted operation in their designs, thereby addressing the third objective.

1.2 BASIS FOR THE CONVERSIONS

As required by the Solicitation, the conversion designs were done in accordance with two sets of rules. These are:

1. ABS Rules for Building and Classing High Speed Naval Craft, 2003 [1] 2. DNV Rules for Classification of High Speed, Light Craft and Naval Surface Craft, July 2000 [2].

This report presents full discussion on the primary and secondary structural loads required for the conversion to satisfy each of these classification society rules for unrestricted, open-ocean operation. The primary loads include all typical hull girder loadings associated with a catamaran, although ABS and DNV each include primary hull girder loads unique to their own set of rules. The secondary loads include wave slamming and impacts to the vehicle deck structure due to the new military vehicle loadout and the vessel accelerations in the unrestricted environment.

A brief paragraph is provided below that outlines the sections of this report. It is organized in the same order as the Interim Deliverables that were required for the development of the project.

1.3 SEALIFT MISSION REQUIREMENTS SELECTED FOR THE CONVERSION VESSEL (SECTION 2)

Section 2 defines the Sealift mission requirements to be used as the criteria for selecting the vessel to be converted. The mission requirements include a realistic military vehicle loadout and definitions for the range, speed and endurance of the vessel to be converted.

The military vehicle loadout considered both the US Army and US Marine Corps who each have significant efforts associated with their force deployment strategies and the logistics required to support these forces. The U.S. Army’s Stryker Brigade Combat Team (SBCT) and the U.S. Marine Corps Marine Air Ground Task Force (MAGTF) or Marine Expeditionary Unit (MEU) were both considered as payload candidates for this project. The MEU was the final choice and the actual payload was selected from the MEU loadout defined for the LHA(R) program.

1.4 VESSEL SELECTED FOR THE CONVERSION STUDY (SECTION 3)

Section 3 identifies the likely candidates for conversion and selects the final vessel to be used for the conversion study.

One of the surprises for this project is reflected in the final choice for the vessel for the conversion study, the British Columbia Ferry Corporation’s PacifiCat. Although these are sound craft, they are classed in accordance with DNV with an R4 service restriction. This denotes a severe service restriction for a vessel intended for consideration of unrestricted, open-ocean operation. When the project was originally started it was anticipated that a ship with service restriction R0 or R1 would be available for the study. Unfortunately, none of the R0/R1 owner/operators was willing to provide enough information considering the structural designs of their vessel to complete the work required for this project. Given the new developments regarding US Navy interest in High Speed Vessels, HSV, and the US Army interest in Theatre Support Vessels, TSV, there was too much potential for commercial opportunity to allow distribution of structural design information through an SSC report and potentially jeopardize a competitive edge in this market share. This led to selection of the R4 PacifiCat’s as the final vessel for the conversion study.

1.5 PRELIMINARY VEHICLE ARRANGEMENT ON VEHICLE DECK (SECTION 4)

Section 4 presents the preliminary arrangement of the military vehicle payload on the Main Vehicle Deck of the PacifiCat, which has Upper and Main Vehicle Decks. It was not necessary to use the Upper Vehicle Deck to accommodate the military payload defined for this project. A revised arrangement is presented later in the report that more efficiently stores the vehicles to minimize the structural conversion work required on the vehicle deck. The preliminary vehicle arrangement assumed 12 inches between bumpers of stowed vehicles. Research confirmed that the US Marines typically assume 10 inches clearance between vehicles, “Marine Lifting and Lashing Handbook, Second Edition, October 1996, MTMCTEA REF 97-55-22 [3].

1.6 STRUCTURAL LOADS REQUIRED FORTHE CONVERSION (SECTION 5)

Section 5 uses both the ABS and DNV rules cited above to calculate the applicable primary hull girder and secondary loads acting on the vessel for operation in unrestricted, open-ocean environments. Tables compare and summarize the hull girder and slamming loads. This section also provides some of the original loads that were used for the design of the PacifiCat’s.

The vehicle tire loads are also defined in this section. There was significant problem getting accurate determination of all the tire footprint loads. Enough representative data was available to develop reliable structural calculations for this project and determine structural modifications that would be required to accommodate the new payload. During this portion of the project it was concluded that the tire loads fit into one of three basic categories:

1. Tires with a width less than the deck longitudinal stiffener spacing, 2. Tires with a width nominally greater than the deck longitudinal stiffener spacing and, 3. Tires with a width that approaches twice the deck longitudinal stiffener spacing.

Since most deck plate calculations assume the first condition in their sizing requirements for deck plate subjected to tire loads, i.e., simple support boundary conditions for the plate panel, it was considered necessary to perform some detailed calculations for the other two scenarios to accurately determine the deck structural requirements in way of these tire loads. These other cases were analyzed using finite element analysis techniques in Section 6.

1.7 STRUCTURAL MODIFICATINS REQUIRED FOR THE CONVERSION (SECTION 6)

Section 6 provides the calculations detailing the structural modifications necessary to satisfy the loads developed in Section 5. Calculations include investigation of the modifications required for the primary hull girder loads, secondary slam loads and vehicle loads on the Vehicle Deck.

Section 6 also provides the finite element analyses, FEA, that were developed to investigate the tire size/deck longitudinal spacing issue discussed above. This FEA work presents insight to some of the structural optimization that can be realized using these tools compared to the algorithms presented by the rules.

1.8 STRUCTURAL MODIFICATION COST ESTIMATES (SECTION 7)

Section 7 provides cost estimates to accommodate the structural modifications required for these conversions in accordance with the requirements resulting from both ABS and DNV. The cost estimates also include typical costs for port facilities, material painting and procurement and installation of the vehicle tie downs required for the conversion.

1.9 CONCLUSIONS

Conclusions are presented at the end of the report that suggest the limited increases that would be required for future designs to accommodate the structure that would allow for use as an open- ocean, unrestricted craft. Owners may give consideration to this possibility and may also approach the Government to help absorb the up-front costs of fabrication and operation of the heavier ship offering their vessels for service in time of need for the military or national emergency.

2.0 SEALIFT MISSION REQUIREMENTS OF CONVERSION VESSEL

2.1 INTRODUCTION

This section defines the Sealift mission requirements for converting a commercial high-speed ferry for use in transporting military vehicle cargos. A comparison is made between the load requirements of the U.S. Army’s Stryker Brigade Combat Team (SBCT) and the U.S. Marine Corps Marine Air Ground Task Force (MAGTF) or Marine Expeditionary Unit (MEU). Both of these loads represent actual or planned sealift loads for either rapid deployment (SBCT) or a lightweight, sea based combat force (MEU). After consideration of both loads, and the data available to support this project, a notional load based on the MEU is defined for this project.

The preliminary survey for the commercial high-speed craft available for conversion suggest that the converted vessel will have less capability than a purpose built dedicated military design. Based upon the assumed loads, the requirements for the commercial conversion craft have been set at approximately 1/3 less than the payload target of a dedicated military craft.

This section of the report is broken into several sections:

• Background Assumptions: Assumptions that focused the direction of the requirements development effort. • Existing Military Vessel Characteristics Summary: Review of existing high-speed transport vessels designed to serve military missions. • Load Planning Assumptions: Assumptions that have refined the requirements based upon particular considerations. • Deck Height Profiles & Notes: Analysis of the SBCT and MEU to identify deck height and cargo weight requirements based upon threshold and objective requirements for numbers of sorties to move the complete unit. • Load Planning Notes: Requirements details to support the designers in the evaluation of candidate high-speed ships for conversion. Includes critical vehicles that may impact the selection of candidate high-speed ships and the conversion requirements for each. • Notional Load list: A representative listing of military vehicles based on a self- deployable slice of the MEU.

The notional vehicle load for the conversion vessel is provided in Table 2-1. It is based on the LHA(R) load, which is developed from the USMC MEU load. Except for tanks and tank recovery vehicles, the conversion load includes all of the vehicles contained in the LHA(R) load, albeit in smaller quantities. Further discussion on the exclusion of the tanks is provided below. For clarity, Table 2-1 shows the total number of vehicles required by the LHA(R) load and the total number of vehicles to be transported by the conversion vessel. The areas and weights shown in Table 2-1 are for the conversion vessel.

Table 2-1. Notional Vehicle Load for Conversion Vessel

NOMENCLATURE LHA(R) Conv LN WD HT WT Area TOTAL WT QTY QTY (SQ FT) (LBS) AN/MLQ-36 1 1 255 99 126 28,000 175 28,000 AN/MRC-138B 8 2 180 85 85 6,200 213 12,400 AN/MRC-145 8 2 185 85 83 6,200 218 12,400 ARMORED COMBAT EXCA 2 1 243 110 96 36,000 186 36,000 TRK, FORKLIFT 1 1 315 102 101 25,600 223 25,600 TRK, FORKLIFT, 4K 1 1 196 78 79 11,080 106 11,080 TRAM 1 1 308 105 132 35,465 225 35,465 CONTAINER, QUADRUPLE 70 20 57 96 82 5,000 760 100,000 CHASSIS TRLR GEN PUR, M353 1 1 187 96 48 2,720 125 2,720 CHASSIS, TRAILER 3/4 T 2 2 147 85 35 1,840 174 3,680 POWER UNIT, FRT (LVS) MK-48 2 1 239 96 102 25,300 159 25,300 TRLR CARGO 3/4 T (M101A1) 4 2 145 74 50 1,850 149 3,700 TRAILER CARGO M105 6 2 185 98 72 6,500 252 13,000 TRLR, MK-14 2 2 239 96 146 16,000 319 32,000 TRLR TANK WATER 400 GL 2 1 161 90 77 2,530 101 2,530 TRK AMB 2 LITTER 1 1 180 85 73 6,000 106 6,000 TRK 7-T MTVR 24 8 316 98 116 36,000 1,720 288,000 TRK 7-T M927 EXTENDED BED 1 1 404 98 116 37,000 275 37,000 TRK 7-T DUMP 1 1 315 98 116 31,888 214 31,888 TRK TOW CARRIER HMMWV 8 4 180 85 69 7,200 425 28,800 TRK, MULTI-PURPOSE M998 45 15 180 85 69 6,500 1,594 97,500 TRK,AVENGER/CLAWS 3 1 186 108 72 7,200 140 7,200 TRK ARMT CARR 10 2 186 108 72 7,000 279 14,000 TRK LIGHT STRIKE VEHICLE 6 2 64 132 74 4,500 117 9,000 155MM HOWITZER 6 2 465 99 115 9,000 639 18,000 LAV ANTI TANK (AT) 2 2 251 99 123 24,850 345 49,700 LAV C2 1 1 254 99 105 26,180 175 26,180 LAV ASSAULT 25MM 4 2 252 99 106 24,040 347 48,080 LAV LOGISTICS (L) 3 1 255 98 109 28,200 174 28,200 LAV, MORTAR CAR 2 1 255 99 95 23,300 175 23,300 LAV, MAINT RECOV 1 1 291 99 112 28,400 200 28,400 TANK COMBAT M1A1 4 - 387 144 114 135,000 - - MAINT VAN 4 2 240 96 96 10,000 320 20,000 RECOVERY VEH, M88 1 - 339 144 117 139,600 - - Totals: 238 87 10,629 1,105,123 Total STons 553

Other notional requirements for the conversion vessel are given as:

• Speed (Fully Loaded) 36 knots • Range 4000 NM • Vehicle stowage capacity 500 short tons (Threshold) 750 short tons (Objective)

2.1.1 Speed

The definition of 36 knots as the speed for the fully loaded vessel represents a consensus based on the speeds of the commercial high-speed ferries that have been identified as part of the preliminary search for candidates for the conversion. In particular, the larger commercial ferries, which represent more likely candidates for the conversion, tend to have speed ratings between 35 knots and 41 knots. As further definition is developed for this study better definition will be available for speed. However, it must also be recognized that the structural weight of the vessel

will almost certainly increase as a result of the conversion. This will have the dual effect of reducing the speed and/or cargo capacity of the converted vessel.

2.1.2 Range

The range is aggressive and will certainly not be satisfied by any of the conversion vessels. As seen in Table 2-2, the Actual Ships have ranges on the order of 600NM whereas the Notional Ships will be designed to have significantly greater ranges. At this time, it has not been possible to gather the data regarding the actual ranges of the commercial vessels that have been collected for the preliminary identification of conversion candidates.

2.1.3 Vehicle Stowage Capacity

The Threshold and Objective values defined for this project are based on the cargo requirements associated with the US Army Stryker Brigade Combat Team, SBCT, even though the actual load out is based on the MEU. As shown in Appendix A, the full complement of one SBCT has a weight of 14,403 short tons. The criteria defined by the Operational Requirements Document, ORD, for the US Army Theatre Support Vessel, TSV, show that it must be able to transport the full complement of 14,403 short tons in 20 sorties and therefore defines a cargo capacity of 750 short tons per sortie. With most of the larger commercial ferries advertising cargo capacities in the range of 500 short tons it was decided to define this as the Threshold cargo capacity for the conversion vessel with an Objective value of 750 short tons. The notional load defined in Table 2-1 results in a cargo weight of 553 short tons and is consistent with the cargo capacity goals defined for the conversion vessel.

2.2 DATA ON US ARMY & US MARINE CORPS NOTIONAL LOADS INVESTIGATED FOR THIS PROJECT

Before selecting the notional load defined by Table 2-1, a thorough review of the US Army SBCT and the USMC MEU was undertaken. This review included defining the deck area and deck height requirements associated with each of the vehicle loads. It also included defining the vehicle weights associated with the various loads and insuring that the notional load defined for this project represented a realistic load and was acceptable from an overall weight standpoint.

Finally, this review also provided some definition on vehicles to be excluded from the mix transported by the conversion vessel. This included M1A1 tanks and their support vehicles as well as aviation assets. Further discussion on all of this review is presented below.

2.2.1 Background Assumptions

The following background assumptions concerning load and design requirements have been made.

• The Stryker Brigade Combat Team (SBCT) represents the US Army load for studies of future rapid deployment. See Appendix A for comprehensive load list.

The Army has established aggressive goals for achieving a lighter, more mobile and more rapidly deployed force as part of their ongoing transformation initiative. This force is to come into being over the next several decades as an interim and then final force. The SBCT is the interim force and represents the mid-term transformation to the lighter Army. As such, the SBCT is being used for Army mid term (circa 2015) mobility planning.

• The Marine Expeditionary Unit (MEU) represents the USMC load for rapid deployment. See Appendix A for comprehensive load list. The doctrine, strategy, and tactics of the MEU are well established, and regularly reviewed to support amphibious ship availability and construction schedules. The data in Appendix A represents the results of the Department of the Navy (DoN) Lift II study which provides a benchmark of future concepts of operations, force structure, and estimated lift requirements of a potential 2015 MEU. The actual notional load recommended for this project is a down sized version of the notional 2015 load for the LHA(R), which was based on the MEU.

• The U.S. Army Theater Support Vessel (TSV) Block I Operational Requirements Document (ORD) represents the planning requirements for size, speed, and payload for an intra-theater sealift vessel. The TSV program ORD requirements have been established around the SBCT. As such, this notional vessel represents the Department of Defense (DoD) developed “military” solution for transportation of the Army’s future combat force.

• It is assumed that the converted high-speed commercial ships will have less capability than a purpose built dedicated military design. For the purposes of this study, the military threshold requirements for the TSV have been established as the objective requirements for the commercial conversion class and the threshold requirements for the commercial class have been set approximately 1/3 below those numbers based on expected capabilities of commercial ferries available for conversion. The rationale for this assumption is that in times of war, missions going into harms way, or critical deployments, a dedicated military asset such as the Army TSV will be used. These conversion ships will be used for low threat follow-on missions or deliberately planned lifts.

2.2.2 Summary of Existing High-Speed Military Vessel Characteristics

Table 2-2 provides an overview of high-speed vessels recently designed and/or used for military missions. Also included are several notional vessels including the three “blocks” of TSV’s presently being developed by the U.S. Army.

Threshold and Objective are the terms defining the minimum (Threshold or T) and optimal (Objective or O) solution sets for a design. In some cases, the requirements development process may determine that these values are the same (T=O or T/O)

Table 2-2. Summary of Existing Sealift Mission High-Speed Vessels

Length Beam Draft Displacement Speed Range Cargo Weight Cargo Sq Ft (Loaded)

Proposed SR 1437 Study Requirements Notional Requirements 121m (397 ft) (T) 18 ft (T), 36 kts (T/O) 4000 NM (T/O) 500 STons (T), 11,700 (T), 15ft (O) 750 STons (O) 17,300 (O)

Notional Ships: Army TSV Block I 121m (397 ft) (T) 18 ft (T) 36 kts (T/O) 2400 NM @36 kts (T), 754 STons (T), 20,000 (T), 15ft (O) 4726 NM @24 kts (T), 1050 STons (O) 25,000 (O) 4726 NM @ 36 kts (O) Army TSV Block II 121m (397 ft) (T) 18 ft (T) 40 kts (T), 4726 NM (T/O) 1050 STons (T), 25,000 (T), 15ft (O) 45 kts (O) 1250 STons (O) 27,500 (O) Army TSV Block III 121m (397 ft) (T) 18 ft (T) 45 kts (T), 4726 NM (T/O) 1254 STons (T), 27,500 (T), 15ft (O) 50 kts (O) 1250 STons (O) 29,500 (O) Shallow Draft High Speed Sealift 300 m 37 m 9.4 m 27,135 Tonnes 55 kts 8,700 NM 120,770 (SDHSS)

Actual Ships: HSV X1 (Joint Venture) 96 m (314 ft) 26 m (87 ft) 4.04 m 1740 LTons (full 35 kts 600 NM 545 STons (35 23,000 (15 ft) load) STons Vehicles) HSV X2 98 m (319 ft) 26.61 m 3.43 m 40 kts 4000 NM * 750 LTons (deadweight) TSV 1X (Spearhead) 98 m 26.61 m 3.43 m 40 kts 4700 NM * 750 LTons (deadweight) USMC WestPac Express 101.0 m 26.62 m 4.2 m 33 kts 1240 NM 550 MT 70000 cu ft Skjold Class-MCMV Class 44 m 13.5 m 1 m 45 kts 800 NM 270 Tonnes (deadweight) Jervis Bay 86.14 m (282 ft) 26 m (87 ft) 3.63 m 44 kts 415 LTons (deadweight) Note: * Extended range listed is based on the use of cargo deadweight for additional fuel and/or reductions in speed

2.2.3 Load Planning Assumptions

The TSV ORD requires 750 short tons cargo capacity as a threshold requirement. Because the subject study is the conversion of commercial assets, this was set as the objective requirement for conversions and the threshold was set 1/3 lower at 500 short tons cargo capacity which is also consistent with the cargo capacities of the largest commercial ferries so far identified for the conversion candidates.

The TSV ORD assumes 20 sorties to transport an entire SBCT (750 tons/sortie). As a result of previous assumption, 30 sorties will be used for commercial mission (500 short tons per sortie). This may equate to a longer deployment time depending on the number of ships available and the vessel speed.

Table 2-3 summarizes the information regarding number of sorties and threshold and objective weights associated with the SBCT and the MEU.

Table 2-3. Summary of Number of Sorties and Weight Requirements Based on TSV ORD

Threshold Objective SBCT MEU SBCT MEU Weight 500 500 750 750 Sorties 30 7 20 5

2.2.4 Elimination of M1A1 Tank and Aviation Assets from the Notional Load

In order to develop a notional vehicle load that is consistent with the capabilities of a conversion vessel it became clear that it would be necessary to eliminate the M1A1 tank and aviation assets (helicopters) from the notional load.

2.2.4.1 Elimination of M1A1 Tank Assets

There were two issues regarding the tanks. First, transporting the M1A1 implies the necessity for transporting the M88 tank recovery vehicles. Each of these vehicles weighs less than 140,000 pounds and transporting one of each would consume almost 140 short tons or almost 28% of the total cargo weight available for the threshold capacity. It was felt that this would severely limit the number of additional vehicles that could be transported on a given sortie and was viewed as an unattractive limitation, not desirable for the conversion vessel.

Regardless of the weights, is the other big issue of the ramps that are required to load and off- load these vehicles. The RO/RO ramps required to load and off-load these vehicles are heavy structures whose design is governed by these vehicles. Their weight would not only decrease the cargo capacity remaining for military vehicles but they also require heavy cranes to position them for operation. Each of these considerations would impose further limitations by having to accommodate the M1A1 and the M88’s.

2.2.4.2 Elimination of Aviation Assets

Due to special handling needs, and outsized loads, the conversion high-speed ships will not be required to accommodate aviation assets (helicopters) for the purposes of this study. As a follow-up study to this project, the final design can be re-evaluated for its ability to accommodate selected aviation assets.

Missions requiring a significant air wing are assumed to be higher priority military missions, which will receive priority consideration for military high-speed sealift assets.

Additional concerns were also raised regarding the NAVAIR requirements that might accompany the transport of aviation assets. This could have increased effects on the arrangeable areas of the vehicle decks as well as secondary systems such as fire fighting. These concerns are beyond the scope of this project. An actual conversion design would have to address this along with other system impacts such as fire fighting, HVAC and other mechanical systems.

As a result of these assumptions, the aviation element was eliminated in its entirety from the load out for the conversion efforts associated with this project.

2.2.5 Deck Height Profiles & Notes

The following deck height profiles for square footage and cargo weight have been developed by evaluating the SBCT and MEU loads as sorted by height of cargo. The requirements (per height category) were divided by the assumed number of sorties (threshold and objective) in order to obtain the actual required deck height profile per ship. For the purposes of this evaluation, and

with the exceptions noted below, it has been assumed that an equal fraction of each deck height requirement is carried on each sortie. Table 2-4 summarizes these requirements.

Table 2-4. Summary of Deck Height/Area Requirements for SBCT &MEU

Square Footage Threshold (Sorties) Objective (Sorties) Deck Height SBCT (30) MEU (7) SBCT (20) MEU (5) Below 48 inches (4 FT) 282 487 423 681 Between 49 and 96 inches (8 FT) 3,009 3,937 4,514 5,512 Between 97 and 114 inches (9.5 FT) 4,471 895 6,706 1,253 Between 115 and 120 inches (10 FT) 382 1,962 382 2,747 Between 121 and 144 inches (12 FT) 930 1,032 1,395 1,445 Between 145 and 156 inches (13 FT) N/A 246 N/A 246 Other Cargo 279 N/A 419 N/A Totals 9,353 8,559 13,839 11,884

Normal loadout planning includes a stow factor of 0.85 for pre-positioned loads and 0.75 for surge loads. Experience shows that factors closer to the preposition factor can be achieved even for surge loads. Based on this experience, a stow factor of 0.8 has been assumed for this study. Using the SBCT load as a worst case (larger footprint than the MEU) and rounding up to the next 100 square feet equals an expected required square footage of 9353/0.8 = 11,700 (threshold) and 13,839/0.8 = 17,300 (objective). While a stowage factor of 0.8 is acceptable for this project, it is also noted that experience with surge loads has shown stowage factors as low as 0.7. Table 2-5 provides a summary of weight requirements of the load as a function of deck height for the threshold and objective SBCT and MEU.

Table 2-5. Summary of Deck Height/Load Requirements for SBCT & MEU

Load (lbs) Threshold (Sorties) Objective (Sorties) Deck Height SBCT (30) MEU (7) SBCT (20) MEU (5) Below 48 inches (4 FT) 9,181 9,749 13,772 13,648 Between 49 and 96 inches (8 FT) 181,747 336,033 272,621 470,446 Between 97 and 114 inches (9.5 FT) 616,826 125,674 925,239 175,944 Between 115 and 120 inches (10 FT) 15,750 236,202 15,750 330,683 Between 121 and 144 inches (12 FT) 98,676 193,646 148,014 271,105 Between 145 and 156 inches (13 FT) N/A 40,960 N/A 40,960 Other Cargo 47,620 N/A 71430 N/A Totals (lbs) 969,800 942,264 1,446,826 1,302,786 Totals (STons) 485 471 723 651

The SBCT deck height between 115 and 120 inches (10 FT) is driven by the 12 155mm howitzers. Since it is not possible to carry 1/20th or 1/30th of 12 howitzers, these requirements are based on 1/12th of the force or one howitzer and are the same for threshold and objective.

The MEU deck height between 145 and 156 inches (13 FT) is driven by the M1085C Hydraulic Wheeled Excavator. Since it is not possible to carry a fraction of this vehicle, these requirements are based on the actual requirements of the excavator and are the same for threshold and objective.

The actual clear height from the Main Vehicle Deck to the underside of the structure on the Upper Vehicle Deck is approximately 4.2 meters, 165”, which allows plenty of overhead for any of the assets contained in either the MEU or the SBCT.

2.2.6 Load Planning Notes

Pounds per square foot (PSF) loading requirements have been evaluated on a per deck height basis both as an overall average for the cargo to be stowed and for the heaviest individual vehicle in the height range. Table 2-6 and Table 2-7 summarize this data. In several cases, the significant value is 2-3 times the average value. This consideration may in turn drive additional load planning decisions (i.e. where a particular piece of cargo may be stowed) or basic load planning assumptions (i.e. can this piece of cargo be accommodated on the conversion class.

Table 2-6. Average Deck Loads/Height for SBCT & MEU

Overall Average of Vehicles in Deck Height Range (PSF) Deck Height SBCT MEU Below 48 inches (4 FT) 33 20 Between 49 and 96 inches (8 FT) 61 85 Between 97 and 114 inches (9.5 FT) 138 140 Between 115 and 120 inches (10 FT) 42 120 Between 121 and 144 inches (12 FT) 107 188 Between 145 and 156 inches (13 FT) N/A 167 Other Cargo 171 N/A

Table 2-7. Heaviest Individual Average Vehicle Load for SBCT & MEU

Heaviest Vehicle in Deck Height Range (PSF) Deck Height SBCT MEU Below 48 inches (4 FT) 134 65 Between 49 and 96 inches (8 FT) 187 291 Between 97 and 114 inches (9.5 FT) 209 163 Between 115 and 120 inches (10 FT) 42 148 Between 121 and 144 inches (12 FT) 132 201 Between 145 and 156 inches (13 FT) N/A 167 Other Cargo 171 N/A

2.2.7 Key Design Vehicle Lists

The key design vehicle lists below in Table 2-8 and Table 2-9 were derived from Appendix A. The master lists were sorted for the five largest vehicles in each measurement (Length, Width, Height, Weight, and Square Footage) and then the result simplified and summarized into these tables. The intent of these tables is to provide the structural and arrangements trades with some indication of particularly challenging equipment requiring access within the ship.

While information on turning radius will be available to ensure notional vehicle loading on the conversion vessel is practicable it is not expected to be a major concern. The conversion vessels are ferries with straight on/off loading access, either fore/aft or amidships and, unlike typical Sealift vessels do not require movement of vehicles along fixed ramps between decks of the ship.

Table 2-8. Key Design Vehicle List for US Army (SBCT)

LIN Nomenclature Model LN WD HT WT SQ. FT. K57821 01 HOWITZER TOWED 155M M198 496 111 117 15750 382 L28351 47 KITCHEN FIELD TLR M MKT-95 201 152 132 5260 212 R41282 01 RECON SYS NBC M93A1 FOX 288 118 105 38500 236 T63093 33 TRUCK WRECKER 8X8 M984A1 WWN 402 102 112 51300 285 T87243 11 TRK TANK 2500 GAL M978 WOWN 401 96 112 38165 267 T96496 05 TRUCK CARGO TAC W/L XM1120 WOW 401 96 129 35300 267 YA0005 01 WATER PURIFICATION 2-1/2-TON 281 100 128 19480 195 Z43601 02 INFANTRY CARRIER VE STRYKER 288 113 106 42000 226

Table 2-9. Key Design Vehicle List for USMC (MEU)

TAMCN NOMENCLATURE LN WD HT WT SQ. FT. B0589 AMORED EARTHMOVER, ACE M-9 243 110 96 54,000 186 B0591 EXCAVATOR HYD WHL 1085C 365 97 154 40,960 246 B2482 TRACTOR, ALL WHL DRV W/ ATACH 277 94 141 13,000 181 B2567 TRAM 308 105 132 35,465 225 C4154 INFLATABLE BOAT RIGID HULL 468 98 80 6,000 319 D1061 MTVR 7 TON EXT BED 404 98 116 31,500 275 D1212 TRUCK WRECKER 5 TON 6X6 346 98 114 38,466 235 E0665 155MM HOWITZER 465 99 115 15,400 320 E0846 AAAV PERSONNEL (P-7) 360 144 126 72,500 360

2.2.8 Notional Load List

Table 2-10 provides a summary of area and weight requirements of the notional load based on deck height requirements. This is based on Table 2-1, which is the notional load list based on the 2015 projected USMC load for the LHA(R). This load has been reviewed with USMC planners and been determined to be a representative “slice” of the MEU, which could be expected to deploy as an independent unit.

Note that this notional load is sized (both by weight and footprint) to be between the threshold and objective requirements discussed above.

Table 2-10. Summary of Area and Weight Requirements Based on Deck Height for the Notional Load

Notional Load Profile Square Load (lbs) Footage Deck Height Below 48 inches (4 FT) 298 6,400 Between 49 and 96 inches (8 FT) 5,140 396,910 Between 97 and 114 inches (9.5 FT) 1,277 181,760 Between 115 and 120 inches (10 FT) 2,849 374,888 Between 121 and 144 inches (12 FT) 745 113,165 Between 145 and 156 inches (13 FT) 319 32,000 Other Cargo N/A N/A Totals 10,629 1,105,123 Short Tons 553

2.3 CONCLUSION ON SEALIFT MISSION REQUIREMENTS

The review of the US Army SBCT and the USMC MEU developed for this project provided good insight to the philosophy of these two organizations and their requirements for high-speed vessel capability. It is obvious that the ability to access high-speed transport is an important component for both force structures. The conversion vessels will help to satisfy these requirements with certain limitations that are consistent for the capabilities of a conversion vessel.

As this project proceeds, the notional load presented in this deliverable may be re-defined as a function of the commercial high-speed ferries available for this mission and its actual speed and payload capabilities. The structural modifications required for these vessels to accommodate the notional load may in fact consume a significant portion of the available displacement and limit the cargo capacity of the conversion vessels.

One of the lessons of this project will come from the weight of structural modifications that are required. If they are not significant it may become desirable for owners to include such capacity in their original designs, minimizing time and expense for conversion.

3.0 CONVERSION VESSEL CANDIDATES & THE FINAL SELECTION

3.1 SELECTION PROCEDURES AND REQUIREMENTS

This section of the report presents the procedure that was used to select a candidate vessel for the Structural Conversion study. In brief, the process undertaken was as follows:

• Determine vessel requirements based on the notional loadout defined in Section 2. • Assemble a “menu” of candidate vessels for the conversion. • Assess candidates versus requirements. • Develop a set of downselect criteria and, • Downselect to recommended conversion vessel for this project.

The information presented in this report parallels the outline given above. Thus, paragraph 3.1 of this report presents the determination of the vessel requirements. Paragraph 3.2 summarizes the list of candidate vessels, with back-up data presented in Appendix B. Paragraph 3.3 presents and discusses the alignment of the candidate vessels against the requirements. Paragraph 3.4 presents and discusses the recommendation of a single vessel for use as the conversion candidate. Paragraph 3.5 presents the characteristics of the final vessel selected and Paragraph 3.6 presents the Conclusions for this section of the report.

3.1.1 Required Vessel Characteristics

This section of the report presents the recommendation of what vessel to use for this Structural Conversion Study. The recommendation presented herein is the result of collecting data on commercial ferries and comparing this data with the needs of the project. This section of the report presents a discussion of what those needs are.

The required vessel characteristics are broken into three categories:

• Payload Characteristics: The vessel must be able to carry the payload identified earlier, (Section 2). • Vessel Engineering Characteristics: The vessel must have been engineered to provide a target level of speed, range, sea state, and similar performance. • Project Data Availability: There must be appropriate technical data available concerning the vessel, so that this structural conversion study project can move forward. It would be no good to find an otherwise-ideal vessel for which there is no available engineering data.

Each of these sets of requirements is discussed in detail in the following paragraphs.

3.1.2 Payload Characteristics

The derivation of the required military payload is discussed in Section 2. The payload investigation results in a notional vehicle load for the converted vessel. The notional vehicle load is presented in Table 2-1.

Note also that the notional load (Table 2-1) was set arbitrarily at 1/3 below the objective levels. This assumption was based on results from the preliminary vessel surveys that had taken place during the development of the work for this section of the study. The survey indicated that the maximum cargo displacement that could be expected for the largest ferries available for conversion is in the range of 500 short tons. Albeit somewhat arbitrary, this was used to define and validate the threshold cargo requirements. This is not a strict limitation, and as will be seen in following sections, the recommended candidate deviates from this capacity.

The notional vehicle load for the conversion vessel, Table 2-1, is based on the LHA(R) load, which is developed from the USMC MEU load. Except for tanks, tank recovery vehicles and aviation assets, the conversion load includes all of the vehicles contained in the LHA(R) load, albeit in smaller quantities.

The notional vehicle load in Table 2-1 is “translated” into a set of functional requirements in Table 3-1. The emphasis of this translation has been to express the notional vehicle load in the form of weight and vehicle lane-meter requirements, because these are the parameters that are most readily available for the candidate vessels. Once a coarse screening has been accomplished using these gross parameters, it will then be possible to attempt an actual load out arrangement on a given selected candidate vessel’s vehicle deck.

In the fast ferry industry it is normal to present the vessel’s vehicle deck capacity in terms of the total available length of all vehicle lanes combined. This yields a figure expressed in “lane meters.”

Also note that the far right hand column in Table 3-1 presents the total vehicle weight in metric tonnes (2204 pounds per metric tonne). Table 2-1 presents the total weight in short tons (2000 pounds per short ton).

By taking the vehicle lengths given in Table 2-1 and adding a 12-inch gap between vehicles, [3], a total requirement of 438 lane meters of vehicle deck is determined in Table 3-1.

This calculation assumes that all vehicles will fit within a lane, but this obviously depends on the actual designed lane width. Commercial ferry lane widths range from a low of 6.56 feet (2 meters) up to 10.82 feet (3.3 meters). If the width of the average lane is assumed to be 9 or 10 feet than review of Table 3-1 shows that only one vehicle, the 11 foot wide Trk Light Strike Vehicle is perhaps too wide. Since there are only two of these vehicles in the loadout it is assumed that careful planning would allow for their accommodation. Therefore, this was not considered a driving factor for the initial scrutiny of the candidate vessels. Instead, attention is focused on finding candidate vessels with about 500 metric tonnes of vehicle payload capacity and 438 lane-meters of vehicle deck. Note that it may become necessary to revisit the lane width assumption for any given vessel.

Table 3-1. Conversion of Notional Vehicle Load into Lane-Meters and Metric Tonnes Wt Each Total Total Wt Conv LN WD HT Total Wt NOMENCLATURE Unit Length (m- QTY (in) (in) (in) (lbs) (lbs) (m) tonnes) AN/MLQ-36 1 255 99 126 28,000 28,000 7 13 AN/MRC-138B 2 180 85 85 6,200 12,400 10 6 AN/MRC-145 2 185 85 83 6,200 12,400 10 6 ARMORED COMBAT EXCA 1 243 110 96 36,000 36,000 6 16 TRK, FORKLIFT 1 315 102 101 25,600 25,600 8 12 TRK, FORKLIFT, 4K 1 196 78 79 11,080 11,080 5 5 TRAM 1 308 105 132 35,465 35,465 8 16 CONTAINER, QUADRUPLE 20 57 96 82 5,000 100,000 35 45 CHASSIS TRLR GEN PUR, M353 1 187 96 48 2,720 2,720 5 1 CHASSIS, TRAILER 3/4 T 2 147 85 35 1,840 3,680 8 2 POWER UNIT, FRT (LVS) MK-48 1 239 96 102 25,300 25,300 6 11 TRLR CARGO 3/4 T (M101A1) 2 145 74 50 1,850 3,700 8 2 TRAILER CARGO M105 2 185 98 72 6,500 13,000 10 6 TRLR, MK-14 2 239 96 146 16,000 32,000 13 15 TRLR TANK WATER 400 GL 1 161 90 77 2,530 2,530 4 1 TRK AMB 2 LITTER 1 180 85 73 6,000 6,000 5 3 TRK 7-T MTVR 8 316 98 116 36,000 288,000 67 131 TRK 7-T M927 EXTENDED BED 1 404 98 116 37,000 37,000 11 17 TRK 7-T DUMP 1 315 98 116 31,888 31,888 8 14 TRK TOW CARRIER HMMWV 4 180 85 69 7,200 28,800 20 13 TRK, MULTI-PURPOSE M998 15 180 85 69 6,500 97,500 73 44 TRK,AVENGER/CLAWS 1 186 108 72 7,200 7,200 5 3 TRK ARMT CARR 2 186 108 72 7,000 14,000 10 6 TRK LIGHT STRIKE VEHICLE 2 64 132 74 4,500 9,000 4 4 155MM HOWITZER 2 465 99 115 9,000 18,000 24 8 LAV ANTI TANK (AT) 2 251 99 123 24,850 49,700 13 23 LAV C2 1 254 99 105 26,180 26,180 7 12 LAV ASSAULT 25MM 2 252 99 106 24,040 48,080 13 22 LAV LOGISTICS (L) 1 255 98 109 28,200 28,200 7 13 LAV, MORTAR CAR 1 255 99 95 23,300 23,300 7 11 LAV, MAINT RECOV 1 291 99 112 28,400 28,400 8 13 MAINT VAN 2 240 96 96 10,000 20,000 13 9

Totals: 87 1,105,123 438 501

Once the initial coarse-filter is complete it will be desirable to consider a detailed vehicle arrangement on the car deck, including any obstructions that would complicate the load/unload operation. It is also necessary to ensure the vertical clearance of the Vehicle Deck will accommodate all vehicle heights identified in the military vehicle payload, and that vehicle access door locations are consistent with military vehicle maneuvering characteristics.

3.1.3 Vessel Engineering Characteristics

In addition to the vehicle payload, additional requirements for the conversion vessel are given in Section 1 as:

• Speed (Fully Loaded) 36 knots • Range 4000 NM • Vehicle stowage capacity 500 short tons (Threshold) 750 short tons (Objective)

The definition of 36 knots as the speed for the fully loaded vessel is described in Section 2 as a consensus based on the speeds of the commercial high-speed ferries that have been identified as part of the preliminary search for candidates for the conversion.

As seen below, the speed of the conversion candidates exhibits a very linear dependence upon the deadweight (load) imposed upon the vessel. In other words, the ships are quoted as being capable of, say, 40 knots on a deadweight of “X” or 35 knots on a deadweight of “Y”. This establishes a relationship between speed and deadweight, for any given vessel.

The range requirement in Section 2 is aggressive and will certainly not be the design range of any of the candidate conversion vessels. As seen below, the candidate ships have ranges on the order of a few hundred nautical miles. This is so that they can devote their lift capacity to the carriage of cargo, and not fuel. Fuelings are relatively frequent.

The ships are, however, capable of carrying greater amounts of fuel. Indeed, the INCAT vessels come fitted with extra tank capacity to make possible vessel repositioning without the use of portable tanks. Thus, longer ranges are possible, but they will come at the expense of payload capacity.

The result is that speed, range, and payload are traded off, one against the other. Most of the large fast car ferries have extra tank capacity and can easily be configured to carry enough fuel for the given range. The problem is that since total deadweight (payload + fuel) is fixed for a given speed the weight of fuel will reduce – one-for-one – the payload lift capacity.

Further, it must also be recognized that the structural weight of the vessel will almost certainly increase as a result of the conversion. This will have the dual effect of reducing the speed and/or cargo capacity of the converted vessel. These trade-offs will be included in future reports as the work is developed.

In addition to the primary requirements of payload, speed, and range, this project also requires that the structural design of the converted vessel allow it to support open ocean, unrestricted operation. The Det Norske Veritas High Speed and Light Craft Rules, DNV HSLC, is commonly used for the design of these vessels. These rules do not support open ocean, unrestricted operation and it is necessary to investigate other DNV rulebook options for developing the structure for this notation. A slight variant on these rules is the more recent DNV High Speed, Light Craft and Naval Surface Craft, DNV HSLC&NSC. These rules include vessel types “Patrol” and “Naval”, for which “Naval” only can receive an unrestricted notation.

In the DNV HSLC rules, Part 1, Chapter 1 Section 2/Table B1, repeated below as Figure 5-5, defines Service Area Restriction notations. Note 1 to this table states:

“Unrestricted service notation is not applicable to craft falling within the scope of the HSC Code, i.e., service and type notations Passenger, Car Ferry or Cargo.”

Service Area Restriction “R0” (“R Zero”) is the most unrestricted and it requires that such a craft can be no more than 300 nautical miles from safe harbor, obviously not open ocean. R1 is the next level of service restriction. Higher R notations correspond to increasing degrees of restriction, the highest one found in the fast ferry world being the R4 notation (coastal protected waters) found on the Canadian PacifiCat. The R0 classification is not an open-ocean unrestricted notation but corresponds to vessel-specific limiting wave heights, generally in the range of 20 feet (6 meters).

For this conversion study the R notation should be as unrestrictive as possible. The more restrictive the notation the greater the impact to the load and scantling requirements necessary to satisfy the conversion.

Also please note that, the discussions presented above are in primary consideration of structural loads and scantlings, which are the specific focus of this project. Other elements of the R notation, and elements of the IMO regulations, would also have impacts on the vessel engineering, distributive systems, etc. For the current project, the study is limited to those items that have a direct influence on the structural design of the vessel.

Finally, regarding the vessel itself, there are structural parameters that can be considered at this stage. These include assessing the arrangement and structural arrangement of the craft, and identifying any potential problems or benefits that would complicate or simplify the conversion.

Also, one should consider the ease or difficulty of accessing the Vehicle Deck structure to accomplish the anticipated modifications that would be required for the conversion. Vessels wherein this structure is rendered inaccessible due to the presence of thin double bottoms or similar impediments may be disqualified on the basis of “practicality.”

3.1.4 Project Data Availability Characteristics

A final class of parameters has been considered in performing the vessel candidate downselect. These parameters concern the availability of project data for the vessels. Several considerations on this point exist:

• Does the necessary engineering data exist? Some of the attractive candidates are older vessels whose builders have since gone out of business. In such case it may be impractical to access the engineering data required for this project. • Is the vessel available for conversion? Some of the vessels on the list of candidates are designs only and have not yet been built. There is always the likelihood that they will not be built and it is considered inconsistent with the original assumptions for this project to use a vessel that does not actually exist. • Is the owner of the design data likely to be willing to grant access to that data? Many ferry designers consider their structural details to be trade secrets and are very unwilling to share. The older the vessel the less likely this is to be a problem. This is also a big problem due to the highly competitive marketplace that has evolved to

support high speed vessels for the US Navy, HSV programs, and US Army, Theater Support Vessel, TSV, programs. • Is the vessel broadly representative of the current and near future state of the art? It may be possible to get data on old vessels, and these vessels may, because of their age, actually be available for purchase and conversion, but is this the most meaningful candidate for the study? Would it not be more valuable to perform the study upon vessels that are representative of the best thinking in the industry, and not on ones that are arguably obsolete.

These parameters, as may be seen, are subjective and interrelated. Nevertheless they have been used in the downselect process as will be described below.

3.2 MENU OF CANDIDATE VESSELS

This section presents the compilation of a “menu” of candidate vessels for the conversion. In producing this list publicly available data on fast car ferries was surveyed and supplemented with in-house knowledge or direct contacts with builders.

A significant element of this effort has been to compile information in a manner that is comparable to the statement of requirements, given in paragraph 3.1. This has relied on some extrapolations and calculations, as will be discussed herein. For example, where length of lane- meters is not quoted by the builder estimates were developed by assuming a 4.5m average car length, times the quoted car capacity. The 4.5m length is a standard figure used to approximate lane-meter capacities in the international ferry trade.1

The calculations of available area are not perfectly accurate, because they do not necessarily take into account the vertical clearances required – in other words the stated amount of lane length may not be of a usable height for the military mission. However, this is not a fatal flaw in the analysis because the vessels are limited by their weight capacity and not by their deck area. In general, the vessels, because they are configured for carriage of low-density passenger cars and parcel trucks, have more than the required lane length, even if they are marginal on payload weight capacity. Therefore, extra effort was not justified to make the deck area calculations more precise. This is illustrated graphically in Figure 3-1, which plots the lane-meters available on the candidate ferries as a function of their deadweight.

1 In the case of the Alaska and Canada vessels a longer vehicle length was used due to unique owner’s requirements for these vessels.

1800

1600

1400

1200

1000

800

600

400 Requirement VEHICLE SPACE (lane-meters)

200

0 0 200 400 600 800 1000 DWT (tonnes)

Figure 3-1. DWT Tonnage and Vehicle Deck Space for Candidate Vessels

Car deck axle loads are generally about 800 kg/axle. Special truck lanes are strengthened to 10 or 12 t/ axle.

Any of the ships can be overloaded to some extent, and thus a heavier payload carried at the expense of speed. In fact, most builders quote several different combinations of weight and speed, frequently not corresponding one to the other.

The complete list of identified candidate vessels is presented in Table 3-2. In this table the values given in black color are taken directly from builder’s literature. Values calculated for this project are printed in blue color.

Table 3-2. List of Candidate Vessels and Key Characteristics. (Values in blue are estimated – Values in black are provided by builder)

DNV Fuel Service Area Vehicle Vehicle Axle Designation Builder LOA DWT Speed Power Capacity Restriction Displ. Capacity Capacity load Lane- m tonnes knots kW cu m tonnes meters Cars t/axle t/axle at quoted at quoted Truck Car DWT speed lanes lanes AMHS Derecktor 71.75 unk 35.5 14400 unk 3 unk 210 35 INCAT 74m INCAT Tasmania 73.6 200 36 28320 32.8 1 unk 378 84 2 0.8 Auto Express 86 Austal 86 485 41 30600 140 2 unk 837 186 12 1 STENA HSS 900 Westamarin 88 480 40 44000 unk unk unk 945 210 unk unk INCAT 91m INCAT Tasmania 91.3 510 42 28320 396 1 unk 990 220 9 2 Auto Express 92 Austal 92 470 40.5 25920 160 unk unk 846 188 12 1 INCAT 96m INCAT Tasmania 95.47 868 38 28320 568 1 unk 690 153 10 0.8 Evolution 10 INCAT Tasmania 96 675 38 28320 660 1 1650 785 174 10 0.8 Evolution 10B INCAT Tasmania 97.22 750 36 28320 660 1 unk 740 164 10 0.8 Evolution 10B INCAT Tasmania 97.22 375 40 28320 660 1 unk 740 164 10 0.8 Auto Express 101 Austal 101 500 37 25920 160 unk unk 963 251 15 3 AFAI 110m A Fai Ships 110 460 60 84000 400 unk unk 450 100 Evolution 112 INCAT Tasmania 112 500 45 36000 unk 1 unk 589 130 12 0.8 Evolution 112 INCAT Tasmania 112 1000 40 36000 unk 1 unk 589 130 12 0.8 Catamaran Ferries PACIFICAT International 122 518 32 26000 94 4 1885 1300 250 7 1.4 STENA HSS 1500 Finnyards 126.6 1500 40 68000 235 1 unk 1688 375 unk unk

3.3 ALIGNMENT OF CANDIDATE VESSELS AGAINST REQUIREMENTS

The next step in analysis of the candidate vessels is to sort them according to their ability to meet the payload, speed, and range requirements. The initial “filter” is to simply eliminate all vessels that carry less than about 500 tonnes of DWT. This effect is dramatic, cutting the list to the eight vessels shown below (sorted by length). The Evolution 10B and the Evolution 112 are represented twice because their builder has presented two different loading conditions for them.

• INCAT 91m • INCAT 96m • INCAT Evolution 10 • INCAT Evolution 10B (2 loading conditions) • AUSTAL AutoExpress 101 • INCAT Evolution 112 (2 loading conditions) • CFI PacifiCat • STENA HSS 1500

These are the only vessels from Table 3-2 that can carry 500t of payload. The next discriminator is range. Some of the short-listed vessels carry only 500t of deadweight. As such, since deadweight includes both payload and fuel, the vessels with only 500t of deadweight would have no capacity left for fuel, and thus would not meet the range requirement.

In order to tackle this issue estimates for the range of the vessel, based on the stated deadweight capacity and power level were developed. The range estimate is very simple: It is assumed that Fuel = (Deadweight minus Payload.) The builder’s stated power and speed were used with an assumed average fuel consumption of 200 gallons / kW-h to calculate range.

This calculation is a simplification that ignores the non-fuel elements of deadweight, such as fresh water and passengers (which introduces error in one direction), and it ignores the electric load contributions to fuel consumption (which will introduce error in the opposite direction), and it does not use an actual fuel consumption rate for the specified engines. For the scope of this project, this is a useful metric, and is probably not too far off from the actual vessel performance.

The resulting predicted performance for the listed vessels is presented in Table 3-3.

Table 3-3. Estimated Fuel Weight and Range for short listed vessels. (Values in blue color are estimated – Values in black color are provided by builder)

Calculated Power at Fuel weight Range at quoted with 500 t listed Designation Builder LOA DWT Speed speed of payload Speed m tonnes knots kW tonnes n mi

91m INCAT Tasmania 91.3 510 42 28320 10 74 96m INCAT Tasmania 95.47 868 38 28320 368 2469 Evolution 10 INCAT Tasmania 96 675 38 28320 175 1174 Evolution 10B* INCAT Tasmania 97.22 375 40 28320 -125 -883 Evolution 10B* INCAT Tasmania 97.22 750 36 28320 250 1589 Auto Express 101 Austal 101 500 37 25920 00 Evolution 112* INCAT Tasmania 112 500 45 36000 00 Evolution 112* INCAT Tasmania 112 1000 40 36000 500 2778 Catamaran Ferries PACIFICAT International 122 518 32 26000 18 111 HSS 1500 Finnyards 126.6 1500 40 68000 1000 2941

* Note that for two of the vessels, the Evolution 10B and Evolution 112, there is data at two different deadweights. This data shows the effect of loading the vessel. Consider the Evolution 112 vessel: The data shows that at a deadweight of 500 tonnes it is capable of 45 knots. But if it is “overloaded” to a deadweight of 1000 tonnes then the speed – on the same power – will drop to 40 knots. Similarly the Evolution 10B loses 4 knots (from 40 down to 36) when “overloaded” to 750 tonnes of deadweight.

These two examples allow investigation of the feasibility of meeting the speed and range requirements discussed above. The behavior of the Evolution 10B and Evolution 112 have been plotted in Figure 3-2, and, since only two points are given, an assumed linear trend is depicted2. Single data points are shown for the STENA HSS 1500, the Austal AE 101, and the CFI PacifiCat, as is a point at the target values of 4000 n mi @ 36 knots.

2 The linear trend assumption is a simplification. It is possible to “reverse engineer” the vessels and produce a more accurate trend line. For this reason the reader should be cautious especially if extending the performance trend outside the values provided by the shipbuilder

Evolution 112 @ 400t Payload Evolution 112 @ 500t Payload Evolution 112 @ 600t Payload 4000 Evolution 112 @ 700t Payload Target Evolution 10B @ 400t Payload 3500 Evolution 10B @ 500t Payload Evolution 10B @ 600t Payload STENA HSS 1500 Evolution 10B @ 700t Payload 3000 w/ 500t Payload

2500 INCAT Evolution 112 INCAT Evolution 10B 2000 RANGE (n. mi.) (n. RANGE 1500 CFI PacifiCat w/ 500t Payload 1000 Austal AE101 w/ 500t Payload

500

0 30 32 34 36 38 40 42 44 46 SPEED (knots)

Figure 3-2. Speed, Range and Payload Performance for Candidate Vessels

This figure shows that the desired payload, speed, and range performance can be met with the Evolution 112 and STENA HSS 1500 craft. The Evolution 10B hull (96m) and AUSTAL AutoExpress 101 (101m) may be considered “second best”, as it appears that it might be possible to extrapolate from them a vessel capable of over 3000 miles and over 30 knots, while the Canadian PacifiCat falls into the third tier of candidates which does not appear capable of a speed/range combination greater than 30/3000.

The remaining parameter concerns access to data. Incat, Austal, and Finnyards (builder of the STENA HSS) were contacted to inquire about the availability of data to support this project. Incat replied “We have recently taken the view with the wide technical community that we should limit information to that which is in the public domain.” Austal replied that their current competition for the US Navy Littoral Combat Ship, LCS, suggested that they should not share data on the AE 101, as they feared it might weaken their competitive position. This was further exacerbated because the Principal Investigator and his employer, JJMA, were supporting a competitor to Austal on the LCS program. Finnyards replied they did have the data, but it was archived and they were not willing to expend the effort to dig it out on an uncompensated basis.

Table 3-4 summarizes the data availability for the vessels listed in Table 3-3.

Table 3-4. Availability of Structural Drawings For Listed Vessels

Is the owner likely to Is the Does the Is the vessel grant access vessel engineering available for to design state of the Designation Builder data exist? conversion? data? art? 91m INCAT Tasmania Yes Yes No Yes 96m INCAT Tasmania Yes Yes No Yes Evolution 10 INCAT Tasmania Yes Yes No Yes Evolution 10B INCAT Tasmania Yes Yes No Yes Evolution 10B INCAT Tasmania Yes Yes No Yes Auto Express 101 Austal Yes Yes No Yes No - Not Built No - Not Built Evolution 112 INCAT Tasmania No Yes yet yet No - Not Built No - Not Built Evolution 112 INCAT Tasmania No Yes yet yet Marginal – Catamaran Ferries Many route- PACIFICAT Yes Yes Yes International specific features Marginal – HSS 1500 Finnyards Yes Yes No Older vessel

3.4 VESSEL DOWNSELECTION

Paragraph 3.3 leads the reader to the conclusion that only vessel with LOA greater than about 100m are technically appropriate for this project, due to range & payload constraints. Eight vessels are identified that would be appropriate candidates for this project. Unfortunately, only one of them, the British Columbia PacifiCat, has technical data available for the projects use.

The conclusion thus seems obvious – use the available data – but it may be informative to discuss the limitations that this selection will impose upon the rest of the project.

The PacifiCat ferries were designed by International Catamaran Designs, Sydney NSW, for the British Columbia Ferry Corporation. The vessels were designed particularly for the waters, routes, and facilities of British Columbia. This tailoring to the specific needs of their owners results in a few features of the vessels that are worthy of note.

Double Ended Loading – The PacifiCats were inserted into a ferry system that currently uses double-ended monohulls. The system assumes a double ended vessel design, where vehicles will drive on over one end of the ship, and drive off over the other end. There is no provision for on- board turn-around of vehicles. This is true of the PacifiCats, and the PacifiCats embody unusual bow and stern features as a consequence. While the vessels don’t sail as double enders, their car deck is very much configured like one, with the bow and stern nearly identical in plan form and terminal interface.

Double Deck Loading – BC Ferry’s terminals are set up to load the upper and lower vehicle decks simultaneously, through the use of two-level shore-based ramps. This means that there are no onboard ramps permitting vehicles to drive from the upper deck to the lower, or vice versa. This is a difficult arrangement to work with regarding conversion. Earlier studies developed by JJMA for PriceWaterHouseCoopers investigated the impacts of installing on-board ramps to accommodate single point loading operations. These studies are included in Appendix B.

Three different ramp modifications were included in the studies. The first allowed for continued double ended loading operation. The other two addressed single ended operations with stern-to and bow-to loading/unloading only. The studies presented in Appendix B were not exhaustive but do represent the issues involved with each type of modification. Maintaining the double ended operation reduces the vessel capacity by the least amount but is the most expensive because it requires a forward and aft ramp as opposed to the other two systems, which require one ramp each.

Particular Terminal Interfaces – The shore-based boarding ramps at the BC Ferry’s terminals are designed to lower and land upon the car deck of the ship. That is to say, that the weight of the ramp is carried upon the ship. In the case of the PacifiCats there is also a shipboard ramp that lowers first, and upon which the shore-based ramp lands. The result of this arrangement is that the shipboard ramp, and it’s hydraulic machinery, have been sized not only for the weight of the ramp, but for the weight of the ramp, the shore ramp upon it, and the loaded vehicles that may be crossing. Contrast this situation to the case where the shipboard ramp is lowered onto a concrete seawall. In that latter case the shipboard machinery would never have to deal with anything heavier than the unload ramp itself, whereas the PacifiCat machinery has to deal with the ramp, the shore ramp, and the vehicles, all at once.

R4 Service Restriction – Partially due to the freeboards imposed by the shore interfaces described above, and partially because the PacifiCats were specifically designed for the climate of British Columbia, they were certificated to only a DNV R4 Service Restriction. This service restriction, along with a 2.5m design limiting wave height, is much lower than the open-ocean, unrestricted operation sought for a vessel under this project.

The following comparison investigates these peculiarities and cautions against the earlier- established criteria for this Project:

The following down select criteria were developed for this task.

• Identify the existing service restriction notation for the craft and assess the magnitude of load increases necessary to satisfy the unrestricted notation required for the conversion. The more restrictive the existing notation, the greater the impact to the load and scantling requirements necessary to satisfy the conversion. The PacifiCat’s unfortunately have a restrictive Service Notation (R4), which may require substantial structural design modifications to bring to the Unrestricted level.

• Assess the structural arrangement of the craft and any potential problems or benefits that would complicate or simplify the conversion.

The PacifiCat’s are reflective of best current thinking regarding aluminum fast car ferry construction. JJMA holds a complete set of engineering drawings of the vessels, including analyses of conversion feasibility associated with the above-mentioned R4 studies. JJMA has also received permission to use these drawings for the current project.

• Assess the ease or difficulty of accessing the Vehicle Deck structure to accomplish the anticipated modifications that would be required for the conversion. Physical access to the structure is excellent. Further, the PacifiCats are mothballed in North America and thus are available for shipcheck, if needed, at minimum cost to the project.

Determine the grade of aluminum used for the existing Vehicle Deck and a rough assessment of its existing strength

• Arrangeable area of the Vehicle Deck and any obstructions that would complicate the load/unload operation. Insure the vertical clearance of the Vehicle Deck will accommodate all vehicle heights identified in the military vehicle payload.

The PacifiCat clear deck height is 14 feet in the truck lanes. JJMA participated in studies of the feasibility of increasing the truck capacity of the vessels and has data on all of the vehicle deck obstructions that might limit loading and unloading.

3.5 DETAILS OF SELECTED VESSEL

BC Ferry Corporation provided the following specifications for the PacifiCat vessels:

PACIFICAT CLASS - VESSEL SPECIFICATION

“PacifiCat Explorer”, “PacifiCat Discovery”, “HSF 003” 122 METER HIGH-SPEED PASSENGER / VEHICLE FERRIES (minor differences in outfit occur between ships)

3.5.1 General Specifications

Builder Catamaran Ferries International Inc. Year Completed “Explorer “– June 1999, “Discovery” – December 1999,

“Voyager” – completed and mothballed August 2000 Owner British Columbia Ferry Corporation. Designer INCAT Designs Sydney, Australia in collaboration with Robert Allan Ltd. of Vancouver, Canada Length Overall 122.50 m Length Waterline 96.00m Beam 25.80m Beam of Hulls 6.00m

Draft 3.76m (approx.) in salt water Certification Transport Canada Marine Safety, in accordance with 1994 IMO International Code of Safety for High Speed Craft (HSC), July 1993 (MSC 63/23 Addendum 2, HSC) for voyages in Canadian Home Trade III waters DNV +1A1 HSLCR4 (enclosed waters 20,20) (Can) Car ferry A EO HSC Category B Craft International Tonnage Certificate Compass installation and adjustment International Load Line Certificate (ILLC) Health and Welfare Canada; Potable Water Standard Ship Station Radio Certificate Can/CSA-B44-94. Safety Code for Elevators

Propulsion Power 26,000 kW Electrical Power 4 x 190 kW Passengers & Crew 1000 Total Vehicles 250 cars (1.5 tonne each) or 4 buses (22.4 tonnes each) and 200 cars Gross Tonnage 9,022 tonnes Displacement Tonnage 1885 tonnes Dead Weight Tonnage 518 tonnes Fuel Oil 66 tonnes Water 5800 litres Lube Oil Storage Tanks 1800 litres Speed 34 knots at 518 tonnes dead-weight at 100% MCR

3.5.2 Structural

Design Two slender aluminum hulls connected by a strong bridging structure consisting primarily of major transverse web frames and 2 longitudinal CVK ‘s and a series of minor girders. Fabrication Welded aluminum construction using 5083 H116 and 5383 H116 plates and 6061-T6 sections. Longitudinal stiffeners supported by transverse web frames and bulkheads. Subdivision Each hull is divided into 8 vented, water-tight compartments divided by transverse bulkheads and decks. The bridging structure between the hulls is fully welded to form a separate compartment. Water-tight upper and lower voids are incorporated into the 5 void spaces ahead of the engine room in each hull between frames 20 and 73. Vehicle Decks Main vehicle deck and upper vehicle decks are constructed with straight-line camber with the external aft and side decks flat.

Superstructure Welded or bonded aluminum construction with longitudinal and transverse framing. Passenger accommodations and wheelhouse are supported above the T3 strength deck on anti-vibration mounts. Axle Loads Main vehicle deck 7.1 tonnes centre 2 lanes, 3.16 tonnes outboard lanes. Upper vehicle deck 1.375 tonnes. Vibration Within DNV guidelines for structural vibration limits for High Speed Light Craft with the vessel fully loaded at service speed.

3.5.3 Accommodation

Interior Outfit Passenger spaces are finished to a first class commercial standard using lightweight materials complying with all Canadian, DNV and IMO-HSC regulations. Interior Decks Floor coverings of heavy-duty carpeting and Amtico (simulated hardwood) vinyl in the passenger lounges, Light-weight Colorflake in the washrooms, Altro 35 vinyl in the food preparation areas, Pirelli rubber flooring in crew spaces, Wooster stairtreads and Bolar gratings on stairway landings. The aluminum vehicle decks are profiled to provide a non-slip surface. Insulation The accommodation areas fully insulated with R8 insulation contoured to the ship’s structure to avoid condensation traps. Seats Café-style light-weight tables and chairs arranged in 4 passenger lounges. Tabletops have a variety of colored vinyl laminates. Chairs are finished with a high quality wear-resistant fabric in a number of different designs. Windows Frameless bonded windows, consisting of clear tempered safety glass, are used in both the accommodation areas and the wheelhouse. The glass in the 4 skylights is tinted. Wall Coverings Hexlite 110 aluminum core honeycomb panels with decorative vinyl laminates. Ceilings The Hydro-Aluminum ceiling system consists of a combination of linear and open grid-systems with white and mirror finishes. Special features include skylights and a sail-cloth ceiling above the observation deck snack bar. HVAC Reverse cycle HVAC system capable of maintaining 22°C at 25% RH with an outside temperature of 32°C at 50% RH and maintaining 20°C with an outside temperature of minus 10°C. Passenger space – make-up fans and fans for 'purging' the passenger cabin provide 8 air changes per hour. Vehicle deck ventilation is capable of 10 air changes per hour in navigational mode and 20 air changes per hour in loading mode. Toilet and service space extraction fans provide 30 air changes per hour. Main engine combustion air is drawn directly from outside the hull through 3 stage water separators. The engine room ventilation system is designed to maintain the engine room temperature below

45°C when the outside temperature is 32°C. Bow Thruster compartment and Voids #5 and #6 have natural intake and mechanical exhaust. Sewage System EVAC vacuum collection system complete with salt water flushing, 1,350 litre collection tank and chlorination / dechlorination treatment unit. Women’s Washrooms The forward washroom includes 6 WCs, 3 Surell hand-basins with large wall mirror and electric hand dryers. The midship washroom includes 5 WC, 4 Surell hand-basins with large wall mirror and electric hand dryers. All vanities have Surell counter tops. Men’s Washrooms The forward washroom includes 3 WCs, 5 urinals, 3 Surell hand- basins with large wall mirror, and electric hand dryers. The midship washroom includes 3 WCs, 4 urinals, 3 Surell hand-basins with large wall mirror and electric hand dryers. All vanities have Surell counter tops. Handicapped Toilets The common-use handicapped toilet is installed at midship on the starboard side of the passenger deck, contains 1 WC with hand rails, emergency call switch, automatic door-opener, wall-mounted hand-basin with lever handle centre set, and paper towel dispenser. Crew Facilities The crews’ mess is located aft of the wheelhouse on the port side and includes lockers for 21 crew, table with 8 chairs, sideboard with sink, microwave, refrigerator, and coffee machine. The officers’ mess is located behind the wheelhouse on the starboard side, and includes: 1 table with 8 chairs, sideboard with sink, coffee machine and fire-locker complete with 2 fire suits.

Ship’s Office The ship’s office is located amidships on the starboard side and includes: 3 workstations complete with desks, shelving, filing cabinets, video display control rack, safe and video monitoring of gift shop and arcade.

Shop/Kiosk A gift shop is located at the centre of the forward end of the main passenger deck. The shop has Amtico simulated hardwood flooring, mirrored ceilings, first-class display shelving, security cameras, exit scanners, and 4 external display cases. Both entrances have vertical security grilles. First-Aid Room The first-aid room is located on the port side of the passenger deck behind the wheelhouse and includes a bed, WC and hand-basin. Other Areas Children’s playroom, video arcade, business/study carrels, engineers’ work shop, bicycle racks and pet facilities. Noise Levels Noise levels do not exceed 75 dBA in passenger areas, and 65 dBA in the wheelhouse. Vehicle Access Vehicle access is via ship-based hydraulically actuated bow and stern ramps working in conjunction with shore-based ramps. Clear width of bow and stern ramps is 5.2m between curbs. Vehicle lane width is a minimum of 2.6m. Main vehicle deck clear height

underneath structural fire protection is 4.0m. The bus lane length is 60m, and is located port of centre line of vessel. The remaining main vehicle deck lane length is 595m. Upper vehicle deck clear height underneath insulation is 2.1m, and total lane length is 655m. Passenger Access There are 3 separate passenger deck accesses from the main vehicle deck; stairwells port, starboard aft and centre forward. A total of 4 shore accesses for walk-on passengers are located on the port and starboard sides of the passenger deck. Elevator An elevator is fitted at the centre of the main vehicle deck providing access to each level of the vessel. Wheelchair access is fitted to the elevator platform at the main vehicle deck level. Paint Hulls above waterline, topsides and superstructure are primed and top-coated white. Hulls below the waterline are coated with primer and silicone-based non-toxic (fouling release) paint. Exposed interior structure, all concealed areas, void spaces, tank linings, jet rooms and foredeck are not painted. Signage Signage to Classification Society's specifications.

3.5.4 Ship Control Systems

Steering/Reverse The electronic steering, speed and reversing control system is integrated into the main engine and water jet controls and is programmed to automatically control engine speed when the reversing buckets are deployed. Control Water jet control is from the wheelhouse centre, port and starboard wing consoles. Bow Thruster A diesel engine-driven bow-thruster is fitted at the forward end of the starboard hull to assist manoeuvring during docking.

3.5.5 Stabilisation Systems

Ride Control A 'Maritime Dynamics' active ride-control system controls the trim-tabs to maximize passenger comfort and propulsion efficiency. Safety An emergency trim-tab lifting device is provided at each transom in the event of electrical / hydraulic failure. The trim-tab control system automatically raises the trim-tabs to the full-up position whenever the reversing jet buckets are deployed, in order to prevent deflection of the reverse thrust.

3.5.6 Anchoring, Towing and Berthing

Anchor 1 cast Super High Holding Power (SHHP) balanced anchor complete with crown shackle, weight 1359 KGs, anchor chain 46mm diameter stud link grade NV K3, 22 meters long with minimum breaking strength 1290 kN is installed complete with anchor cable 196m long by 45mm diameter Herzog P-7 with

HMPE core, minimum breaking strength 1290 kN, specific gravity 1.12. The anchor is stored between the hulls under the aft port side of the main vehicle deck. The cable and anchor chain are stored on a hydraulic anchor windlass and secured in place by a pelican hook. Towing Panama-style fairleads and bollards are installed on the aft mooring platforms port and starboard, main vehicle deck forward port and starboard and upper vehicle deck forward port and starboard. The vessel is capable of being towed by both the forward and aft bollards on the main vehicle deck. A towing bridle is fitted. Berthing Variable speed hydraulic mooring capstans are installed on the port aft mooring platform and on the port forward upper vehicle deck. Each capstan has a 2.5 tonne capacity at a line speed of 20m/min for berthing. The forward capstan has a 3m long pendant control. 500mm aluminum sponsons run the full length of the hulls to protect the hulls and jets during berthing and turning in port. Two- way radio communication is provided at each mooring and anchoring station. 3.5.7 Fire Safety

Fire Detection An addressable fire detection system covers all high & moderate risk spaces. An alarm panel is located in the wheelhouse. Toilets, stairway enclosures, and corridors are equipped with automatic smoke detectors and have manually operable call points. Engine rooms have smoke detectors and heat detectors. Water jet spaces have smoke detectors. Vehicle spaces have smoke and heat detectors. The fire detection system is supplemented by a Closed- Circuit Television (CCTV) with cameras located throughout the ship. A split screen monitor and switching arrangements is mounted in the wheelhouse to enable constant, shipwide monitoring. Structural Fire A Classification Society approved structural fire protection Protection system is used to protect the aluminum structure in areas of high fire risk. Closing Devices Ventilation fire-rated closing devices (fire dampers) are controlled from the wheelhouse, locally and automatically, in the event of fire. Shut-downs Emergency shut-down push-buttons, located at the engine room entrances and operable from the wheelhouse, are installed to stop ventilation fans, fuel and lube-oil pumps located in the engine rooms. A similar means of shutting down the accommodation fans and food preparation equipment is provided. Fire Suppression A Hi-Fog sprinkler system provides fire extinguishing, on the System passenger and vehicle decks, in the engine rooms and the bow- thruster compartment (with AFF foam) from pumping modules in

the port and starboard #5 Void spaces below the main vehicle deck. Each automatic pumping module is sized for whole-ship operation and is monitored/controlled from the wheelhouse. Hydrants Fire hydrants, distributed throughout the ship, are supplied from the Hi-Fog pumping modules. General Equipment Portable fire extinguishers, fire suits and equipment, water-fog applicators, and fire control plans are provided.

3.5.8 Life-saving Appliances and Arrangements

Appliances SOLAS approved lifejackets complete with light and whistle are provided for 1200 passengers (120% of the compliment) of which 100 are children’s lifejackets. Life jackets for all crewmembers are supplied. Lifebuoys, complete with light and smoke signals, flares and pyrotechnics, line-throwing apparatus, and immersion suits are supplied in accordance with SOLAS and IMO-HSC. Liferafts 8 Life Saving Appliance (LSA) 150-person life rafts, 4 deployable Marine Evacuation System chutes (MES), and 2 rescue boats, complete with launching and retrieval davits, provide for evacuation of 1200 persons. Transport Canada approved. Arrangements Safety cards, fire-fighting and escape plans are posted in the control stations and throughout the passenger lounges. Rescue Boats 2 Zodiac H-472, each with 1 - 40 hp Mercury outboard motor, are provided, one on each side of passenger deck. Rescue Boat Davits 2 aluminum alloy, SOLAS type 42, 1,000 kg SWL MOB cranes complete with electric hoist with manual back-up are installed. Communication A 5-station, all-master, telephone type intercom is installed with points at each MES station, the wheelhouse and elsewhere in the passenger and observation decks. 3.5.9 Machinery

Main Engines 4 MTU 20V1163 TB3 resiliently-mounted marine diesel engines, rated at 6500 kW each. Water Jets 4 KaMeWa 112 SII steerable, reversible water jets complete with internal thrust bearings. Transmission 4 Renk ASL 53 gearboxes. Shafting Engine output shaftlines: (1 - long shaftline, outboard and, 1 - short shaftline, inboard in each hull,) Geislinger 4 filament-wound carbon-epoxy CFRP shaftlines complete with membrane couplings, shaft-support bearings and bulkhead seals. Gearbox output shaftlines: 4 steel shaftlines complete with flexibox couplings, Hi-Lock fittings muff style, shaft-support bearings and stern-tube seals.

3.5.10 Auxiliary Systems and Ship Services

Cooling System Engines, generators, reduction gears and hydraulics are cooled by raw water through heat exchangers. Starting Systems The main engines are air started 40 bar. Each engine room is equipped with an air compressor and receiver. There is normally a closed crossover between the systems. All generators are electrically started and provided with 'dead start' capability. Fuel System 2 integral aluminum fuel-oil tanks, one per hull, of 37,135 litres capacity each are located in hull Void #6 port and starboard. Fuel filling stations are located at both ends of the vessel Filling is via a valved filling main sized to allow a flow rate of 2000 ltr/min at 450 Kpa fitted in a save-all with 'Camlock' type connections. Fuel tank gauging software forms part of the control station monitoring system. A remote level indication displayed adjacent to each bunker station with tank bunkering valve controls. Lube Oil System 2 - 908 litre storage tanks installed at the jet space entrances port and starboard. Each main engine has an independent lube-oil system complete with 350 litre service tank located in the jet spaces. Exhaust Systems Main engine and generator exhaust pipes and silencers are resiliently mounted using stainless steel mesh blocks and resilient hangers. Exhaust pipes are thermally insulated. Main engine exhaust pipes are fitted with pyrometers and connections for checking back pressure immediately after the turbocharger outlet. Fresh Water 1 - 5800 litre HDPE tank is fitted in the starboard Void #5 upper and includes high/low level alarm and level indication in the wheelhouse. There are 2 filling stations, one located forward and the other aft. There are 2 fresh water pump sets, one primary and one standby and 9 on-demand hot water heaters. Water to hand-basins is thermostatically controlled to 40°C. Hot and cold water pipes are polyethylene lined aluminum and fittings are gunmetal bronze. Heat tracing is fitted in areas exposed to potential freezing. Sewage Treatment The sewage system consists of 1 - 1,350 litre vacuum collection tank and treatment unit for onboard treatment and discharge overboard. The treatment unit is fitted with a macerator pump, salt water flushing system, chlorination and dechlorination systems. Waste Oil/Oily Water The system consists of 1 - 400 litre aluminum tank, located in System each engine room aft complete with an air-operated transfer pump for transfer to the main vehicle deck aft discharge station. Oily water separator not fitted on HSF 003. Bilge System Every lower void space is fitted with an electric, 3-phase 240vac submersible bilge pump. The presence of bilge water is indicated in the wheelhouse by means of float-switches in each bilge area.

Control of the bilge pumps is from the wheelhouse. In bilge areas where oil contamination can occur, pump control is also located at the compartment access. Engine rooms are fitted with two bilge pumps. One spare portable electric bilge pump is provided with flexible hoses and is stowed in the car deck locker. Anti-Fouling System Hydrosonic Hull Tender systems on all through-hull raw water systems. Hydraulic System A separate hydraulic system for each water jet is installed. Hydraulic power is taken from the PTO pumps and a stand-by electric driven pump normally used for lubrication. One trim-tab power pack is located in each jet space, aft ramp hydraulic system, capstan and anchor windlass take hydraulic power from the trim- tab power packs in the starboard jet room. The forward ramp hydraulic system and forward capstan are powered by an independent power pack located in the bow-thruster compartment. The power packs are single tank systems. An electrically operated, cart-mounted emergency hydraulic power-pack complete with quick disconnects is stowed on the main vehicle deck. The emergency power pack is intended to provide hydraulic power to the ramps, capstans and windlass in the event of a hydraulic failure.

3.5.11 Remote Control, Alarm and Safety Systems

IMACS An Integrated Machinery Alarm and Monitoring System (IMACS) enables all of the functions of the propulsion, auxiliary and electrical systems to be monitored and controlled from the engineers’ console in the wheelhouse. Closed-Circuit TV A CCTV allows selected areas of the ship to be visually monitored from the wheelhouse. Automatic Telephone An automatic telephone system links all the control positions System on the ship, i.e. the wheelhouse, engine rooms, steward’s office, boarding stations, etc. In-Dock Security System An in-dock security system is installed that, with a pushbutton/flashing light/siren arrangement, will enable communication between the wheelhouse and the various vehicle and passenger loading stations. Emergency Sound- An emergency sound-powered telephone system with handsets Powered Telephone in the wheelhouse, engine rooms and waterjets spaces ensures. System Video Information A Video Information System (VIS) is installed, consisting of flat- screen monitors located throughout the passenger areas on which advertising messages, route information and safety announcements can be displayed. The system includes DVD, VCR, and CD, AM/FM tuner.

Intercom A 5-station, all-master, telephone type intercom with points at each MES station, wheelhouse and elsewhere in the passenger and observation decks is fitted. Public Address A ship-wide public address loudspeaker system is installed. Automatic interruption of the entertainment system permits important announcements to be made from any of the automatic telephones on the ship. Alarm General alarms clearly audible to all passengers and crew are enunciated through the PA loudspeakers by means of an alarm tone signal activated by a wheelhouse push-button. Anti-Theft Security An anti-theft shop security system is fitted at the entrances to System the gift shop

3.5.12 Electrical Installations

Generators 4 - 190 kW (nominal) marine, continuous-rated, self-excited, brushless diesel engine-driven alternator complete with class “F” windings are installed in the engine rooms. The generators have 110% one-hour overload capacity. Power Distribution 600V, 60 Hz., 3 phase, 3 wire, no neutral. Switchboards The 2 - main switchboards, located in each engine room are equipped with 600Vac, 240Vac and 120Vac distribution systems with a power management system. Switchboards can be paralleled or operated as stand alone. Power Distribution Power distribution panels located throughout the ship are fed from the main switchboard at 600V, 240V and 120V via engine room transformers. Essential Power Essential services are supplied from distribution panels that Distribution are, in turn, fed from emergency and essential load centers. The 240V and 120V load centers receive, via automatic transfer switches, power supply from each switchboard ensuring that even with the loss of one switchboard, power to the essential systems is maintained. Shore Power 2 - 300 amp, 600V, 60Hz, 3 phase, connections paralleled onto the ship's electric power system. UPS Power Battery-maintained Uninterruptible Power Supplies located in the bridge superstructure deliver power at 120VAC 24V/12VDC for the essential equipment IMACS, navigation, communication, engine and waterjet control. Lighting 120VAC Lighting in non-passenger areas is fluorescent. In passenger areas the lighting consists of fluorescent fixtures, recessed pot-lights, neon, and special decorative fixtures. Fixtures in engine rooms and vehicle decks are vapor proof to IP56 standards. External areas are illuminated with quartz floodlights controlled from the wheelhouse. Emergency 30% of the installed lighting fixtures are fed from the emergency distribution system. 10% of the emergency lighting fixtures are

located at stairways, doors and passageways and have a built-in battery back up which ensures a minimal level of lighting output for a minimum of 4 hours. Navigation Lights Navigational lighting fixtures receive normal and emergency power from monitored circuits with status and control from the wheelhouse. Searchlights Three searchlights are fitted, two forward-facing on housetop for docking purposes, manual aft facing on aft bulwarks. The forward searchlights are controlled from the wheelhouse consoles. Cathodic Protection A microprocessor controlled Impressed Current Cathodic Protection system (ICCP) is installed to protect the water jet tunnels against corrosion. A Sacrificial Anode Monitoring System (SAMS) monitors the condition of sacrificial anodes in the bow thruster tunnel and on the transom by means of a selector switch and Digital Volt Metre (DVM.) All three systems are located in the starboard jet room.

3.5.13 Navigational Equipment

GPS 2 x Northstar 941X, GPS/DGPS Wind Spd/Dir Speed Log Walker combined wind speed and direction and speed log monitoring and display Whistle Airchime motor-driven piston whistle with console-mounted “at will” and coded-signal control unit. Radar 2 - navigational radar’s, Raytheon ST Mk 2 ARPA 3425/7XD, interswitch, colour displays, high-performance monitor, and 7 ft high-speed antenna. 2 - docking radar’s, 1 Raytheon Pathfinder ST Mk 2 TM2525/7XU, and 1 /7xD interswitch, colour TM display (medium resolution), 7 ft high speed antennas ECDIS System Raytheon Pathfinder ST ECDIS bridge station, 1 - 28 inch colour monitor, Management System 2 - high-resolution 20 inch monitors complete with a set of electronic charts. Navigational Sounder Seachart 3, IMO compliant, 50kHz. echo sounder, digital display, 2 transducers, transducer COS. Auto Pilot Anschutz Nautopilot 2010 digital adaptive autopilot, radius and rate of turn control. Gyrocompass Anschutz gyrocompass standard 20GM and 3-console mounted bearing repeaters. Magnetic Compass Anschutz standard magnetic compass Reflecta Fiberline, binnacle and sonde. Navtex Receiver JRC NCR 300A. Nauto conning system Anschutz JBS Display and monitoring system – 4 to 20 inch monitors

Night Vision Equipment Current Corporation Light Enhancement Night Vision Complete with Pan/Tilt camera IR Search Lite 9” Monitor 5” Flat Screen Monitor 2 x H/H Remote Controls

3.5.14 Radio Communications

Radiotelephones 4 - Sailor RT 2048 VHF console mounted radiotelephones. Receiver Kenwood R-5000 communications receiver. Modem, DSC Sailor RM 2042 DSC modem, console mounted. EPIRB Alden, category 1, Satfind 406 Class 1, Emergency Position Indicating Radio Beacon. SART 2 x Alden Search and Rescue Transponder. Shipboard Radio 1 Radio Repeater; 6 Antennas; 8 VHF H/H Radios; 1 Base Station VHF in Repeater Engineers console.

3.5.15 Wheelhouse Arrangement

Access Access to the wheelhouse is through the crew or officers’ lounges or by means of doors from the external wings. Operation There are two forward-facing seats in front of the centre navigation console located at the forward end of the wheelhouse. The centre console contains all of the required navigation, main engine control and internal and external communication equipment. There are secondary consoles at the extremities of the bridge wings where the necessary controls, indications and communications to navigate the vessel are repeated. The engineers’ console, with seating for two engineers, is located behind the central control console. All controls, indications and communications necessary to monitor all of the ships mechanical systems and the facility to manually override the related automatic systems are located in this console. Also included is a computer workstation with bridge gear diagnostics. Visibility Selected wheelhouse windows are equipped with wipers and heaters. There is a built-in window washing system. Communication The onboard communication system is operable from the wheelhouse, enabling communication to all machinery, mooring, boarding and passenger spaces. A dedicated in-dock security system providing communication between the wheelhouse and the various loading stations to ensure safe embarkation and debarkation of passengers and vehicles.

3.5.16 Services

Food Prep The food prep area is outfitted with a dishwasher, dish table, washroom, reach-in refrigerator/freezer, soup kettle, work surfaces, and an area for storage of mobile transport modules. Servery A self-service food counter, complete with hot-wells, soup wells, refrigerated sandwich display, warming lamps and heated shelves is located in the servery. A food counter, 2 combo ovens, pizza oven, conveyor toaster, microwave oven, refrigerated prep table, complete with built-in fire suppression systems, are installed. Coffee Bar A coffee bar is located at the forward passenger lounge complete with espresso machine, other beverage dispensers and dry displays. Snack Bar Another coffee bar is located on the observation deck complete with espresso machines, refrigerator, sandwich display, service counter, beverage dispensers and cash counter. Open Deck Area Bench seats are fitted on the open deck aft of the observation deck.

3.5.17 Manuals/Drawings

Manuals/Drawings ISM & HSC Drawings and manuals are provided in both hard copies and electronic format.

3.6 CONCLUSION

An analysis was performed of the mission and payload requirements for the candidate vessels. From this analysis it was determined that only a vessel over 100m would be a suitable candidate for the conversion. From open literature a list was compiled of eight candidate vessels which could arguably satisfy the requirements. The vessels that best fit the requirements do not yet exist – none have been built. Of the vessels which have been built, for most of them, technical data is not available for use in this project.

Technical data is available and the vessel payload capacity is satisfactory for the British Columbia PacifiCat class ferries. This vessels range falls short of the target for this project. The vessels DNV service area restriction is also more restricting than initially hoped at the outset of this project for the selected conversion vessel. This will increase the work associated with the structural modifications for the craft

In consideration of this balance of facts, the BC Ferry PacifiCat is selected as the conversion vessel for this project.

4.0 PRELIMINARY VEHICLE ARRANGEMENT OF MEU LOADOUT

A drawing is provided below in Figure 4-1 that presents the preliminary arrangement drawing of the Military Vehicle Payload identified for this conversion study. The arrangement is shown on the Main Vehicle Deck of the PacifiCat ferries used for the conversion. The PacifiCat ferries include two vehicle decks although there is no onboard ramp to get from one deck to the other. In its commercial application, all vehicle loading of both decks is accomplished at pierside loading facilities that have been specially developed to load both the upper and lower vehicle decks, i.e., there are upper and lower vehicle ramps to access the two vehicle decks. The preliminary vehicle arrangement locates the entire vehicle payload on the Main Vehicle Deck, which is the Main Deck of the vessel.

The preliminary vehicle arrangement does not consider specific structural impacts to the arrangement shown on the drawing. The requirements for the deck/tie down structure are developed in Section 6 of this report.

The notional vehicle load for the conversion vessel (Table 2-1) is provided again as Table 4-1 for easy reference following Figure 4-1, shown below. It is based on the LHA(R) load, which is developed from the USMC MEU load.

The purpose of this arrangement drawing is to show that the vehicle load out detailed in Table 2-1 will fit into the Main Vehicle Deck of the candidate vessel. The Upper Vehicle Deck is not required to accommodate the load out for this project. The vehicle arrangement includes a 12- inch (30 cm) gap between all vehicles. This was later confirmed as an acceptable gap using reference [3], which recommends that a 10-inch gap be assumed for all vehicle arrangements.

Figure 4-1. Preliminary Notional Loadout for MEU on Main Vehicle Deck of PacifiCat

Table 4-1. Notional Vehicle Load for Conversion Vessel

5.0 STRUCTURAL LOADS REQUIRED FOR THE CONVERSION

5.1 BACKGROUND

One of the primary objectives for this project is the definition of the loads that need to be resisted for the converted vessel in order for it to operate successfully in open-ocean, unrestricted service with the military vehicle payload identified above. The structural loads presented in this report include the following three categories:

1. Primary hull girder loads, 2. Secondary slam loads acting along the shell of the ship and, 3. Tire footprint loads of the military vehicles on the Vehicle Deck structure of the ship.

The primary hull girder and secondary slam loads change from the original design loads for the vessel due to the requirement that the converted vessel be capable of unrestricted, open-ocean operation. As designed and built, the PacifiCat vessels studied for this project have an R4 service restriction in accordance with the DNV rules to which they were designed.

The loads for the first two categories have been developed using the ABS Rules For Building and Classing High Speed Naval Craft, 2003 [1] and the DNV Rules for Classification of High Speed, Light Craft and Naval Surface Craft [2]. The global and local slam loads were calculated for DNV using both R1 service restrictions and unrestricted notations. Since ABS does not have notations that strictly parallel these definitions, the ABS loads were calculated for conditions corresponding to Naval Craft (Unrestricted notation) and Coastal Naval Craft (taken to approximate R1 service restriction).

The third set of loads is independent of the rules used for the conversion although the accelerations predicted by the different rule sets does factor into the final design of the ship structure and tie-downs required to accommodate and secure the military vehicles.

Also critical for the conversion are the materials used for the fabrication of the vessel. There are two principal aluminum alloys used for this vessel:

1. 5083-H321 (or H116) for the hull girder plating of the vessel 2. 6082-T6 (or 6061-T6) for all extrusions

There are two vehicles decks on the PacifiCat. All of the Upper and Main Vehicle Deck structure is fabricated from extrusions and the properties for these materials will be taken from the appropriate ABS and DNV rules.

This report also presents preliminary estimates for the effect to the Vehicle Deck plate and longitudinals resulting from the vehicle loads. The procedures used in this report indicate the baseline for future calculations, which will also be supplemented with detailed analysis for specific areas of design and loading geometry. No analysis for the Vehicle Deck transverse structure is included in this report. Its presence is reflected as boundary conditions in FEA work developed to analyze the vehicle deck plate and stiffening later in the project.

5.2 ABS & DNV RULES FOR HIGH-SPEED VESSEL DEFINITION

The first objective for this section of the report is to confirm that the vessel being converted satisfies the definition for high-speed. Both ABS and DNV have their own definitions for what constitutes a high-speed vessel. Discussion on that and the ABS/DNV Rules required for this project are presented below.

There are three sets of rules that were referenced for this project. ABS has two sets of rules, one each for High Speed Craft [1] and High Speed Naval Craft [2]. All DNV criteria are contained within a single set of rules with different sections addressing naval and commercial vessels. These three rule sets are:

1. ABS Rules for Building and Classing High Speed Naval Craft, 2003 [1] 2. DNV Rules for Classification of High Speed, Light Craft and Naval Surface Craft [2]. 3. ABS Guide for Building and Classing High Speed Craft, February 1997 [4]

Since it is the objective of this project to determine the structural modifications to accommodate a military vehicle payload the assumption was made that the conversions should be developed in accordance with the naval vessel criteria of each respective society, i.e., references [1] and [2].

Reference [4] is for information only. It preceded the development of [1] and forms the basis for many of the load predictions and scantling calculations presented in [1]. All global and local loads and associated scantlings for this conversion study were determined from [1] and [2].

In accordance with Objective 1.1 and Task 3.2.3 of the Statement of Work for this project, it is necessary to determine the structural load and scantling requirements for conversion of the selected ship for “unrestricted, open-ocean operation.” This terminology reflects DNV practice, which refers to “service restrictions” for all high speed craft. Discussion is presented below regarding the different philosophies behind the ABS and DNV approaches to the design of high speed craft.

5.2.1 Definitions – ABS & DNV High Speed Craft

ABS and DNV each have their own definition that determines whether a craft is high speed. The definition for ABS is contained in their Rules for High Speed Naval Craft [1] and their High Speed Craft Rules [4]. The DNV high speed criteria are taken from the DNV Rules for Classification of High Speed, Light Craft and Naval Surface Craft [2].

5.2.2 ABS High Speed Naval Craft

In accordance with ABS HSNC Part 1, Section 1, paragraph 4/1 [1], a vessel will be considered high speed when:

V ≥ 2.36 L

Where:

V = speed in knots = 37 knots for PacifiCat L = length in meters = 96 meters for PacifiCat.

Using these values results in a ratio of 3.78 which is greater than 2.36, resulting in a craft that is high speed in accordance with the ABS criteria.

5.2.3 DNV High Speed, Light Craft

In accordance with DNV Part 1, Chapter 1, Section 2/105 [2] a high speed craft is defined as a craft capable of a maximum speed, in knots, not less than:

V = 7.16∆0.1667

Where:

∆ = Displacement of the vessel, tonnes

Using ∆ = 1885 tonnes results in a speed of V = 25.2 knots. The PacifiCat ferries have a maximum speed of 37 knots.

Therefore, based on the definitions provided in the DNV rules, the PacifiCat ferries qualify as high speed and, if certification of the conversion were desired, the notation for the vessel would include HS, assuming all design and fabrication requirements were satisfied.

When considering ABS and DNV the Light Craft notation is unique to DNV. The ability to be classed as a Light Craft is not a requirement for this conversion study. The calculation is included in this report as a matter of completeness.

In accordance with DNV Part 1, Chapter 1, Section 2/103 [2] a light craft is defined as a craft with a full load displacement that does not exceed:

∆ = (0.13LB)1.5

Where:

∆ = Displacement of the vessel, tones L = Length of the vessel, meters = 96 meters for PacifiCat B = Beam of the vessel, meters = 25.80 meters for PacifiCat

For the PacifiCat vessels selected for conversion, using the values indicated above results in a displacement that cannot exceed 5777.6 tonnes, which greatly exceeds the full load displacement of 1885 tonnes used for the original design of the vessel. The converted vessel will have a full load displacement similar to the original value, well within the limitation to define the vessel as Light Craft.

5.3 ABS STRUCTURAL LOADS

The following section will determine the primary hull girder and secondary slam loads that need to be considered for the conversion of the vessel.

In their Rules for High Speed Naval Craft, ABS defines three different types of naval craft:

• Naval Craft • Coastal Naval Craft • Riverine Naval Craft

Of these, only the Naval Craft can be operated in an unrestricted, open-ocean environment. The operating scenario defined for each of these craft is defined and shown in Figure 5-1, taken from ABS Part 1, Chapter 1, Section 3, Table B [1]:

TABLE B Classification Type

TYPE DESCRIPTION REFERENCE HSC Indicates that the vessel complies with this Guide and the limits HSNC established in Section 1-1-4 Naval Craft This notation is to be assigned to a naval vessel that is intended to HSNC operate in the littoral environment, but is capable of open ocean voyages. Naval Craft are limited to a maximum voyage of 300 miles from a safe harbor when operating in the Winter Seasonal Zones as indicated in Annex II of the International Conference on Load Lines, 1996. When operating on an open ocean voyage, craft are to avoid tropical cyclones and other severe weather events. Coastal Naval This notation is to be assigned to a naval vessel that is intended to HSNC Craft operate on a coastal voyage with a maximum distance from safe harbor of 300 miles and a maximum voyage of 150 miles from a safe harbor when operating in the Winter Seasonal Zones as indicated in Annex II of the International Conference of Load Lines, 1996. Coastal Naval Craft are not permitted to perform transoceanic movements. Riverine Naval This notation is to be assigned to a naval vessel that is intended to HSNC Craft operate in rivers, harbors, and coast lines with a maximum distance from safe harbor of 50 miles. Riverine Naval Craft are not permitted to perform transoceanic movements. HSNC: Guide for Building and Classing High Speed Naval Craft

Figure 5-1 ABS Classification Type from ABS 1-1-3/Table B

Part 1, Chapter 1, Section 4/3 of the Rules [1] also requires that the structural design for all Naval Craft include a Direct Analysis, which is far more extensive then intended for this SSC conversion project. The Direct Analysis would be required for all new construction vessels and it is assumed that the objectives of this project can be satisfied using the rule-book approach for the structural design available through Part 3 of the Rules.

5.3.1 Use of the ABS Coastal Naval Craft Notation for R1 Equivalency

The original intent for this project was to use a candidate vessel for the conversion that had DNV notation of R1 or greater. As a result of only being able to have satisfactory access to an R4 vessel it was decided to slightly refine the task. Instead of taxing the converted R4 vessel with the full structural weight required to convert from an R4 notation to an unrestricted notation it was decided to stagger the weight impact from R4 to R1 and from R1 to unrestricted. The reduction to the payload capacity resulting from structural modifications would only reflect the increase from R1 to unrestricted.

Since the R notation is used by DNV and not ABS, it was decided to equate DNV R1 to the ABS Coastal Naval Craft and equate the DNV R4 to R1 conversion to the ABS existing vessel to Coastal Naval Craft criteria. While this is not an exact match, it is pretty close and considered acceptable for use in this project. In accordance with DNV, an R1 craft can operate up to 300 nautical miles from safe harbor in Summer and Tropical conditions and not more than 100 nautical miles in Winter conditions. As noted in Figure 5-1, the ABS Coastal Naval Craft can operate up to 300 miles from safe harbor on a coastal voyage and no more than 150 miles from safe harbor when operating in a Winter Seasonal Zone. Note that DNV cites “nautical miles” and ABS “miles” as the unit of measure from safe harbor. Again, it was felt that these definitions were close enough for the purposes of this project to allow for the equating of R1 and Coastal Naval Craft.

Therefore, all intermediary loads for ABS are based on their Coastal Naval Craft requirements.

5.3.2 ABS Global Loads

Similar to other rules published by ABS, the rules for High-Speed Naval Craft includes a series of design algorithms to develop the design moments to be resisted by the hull girder. The HSNC rules also include a design algorithm to predict the slamming induced bending moment. The still water and wave induced hogging and sagging moments do not include any variables that account for the high-speed nature of the craft, i.e., they do not include any variables that are a function of speed or vertical acceleration. The slamming moment expression does include the variable ncg, the vertical acceleration of the craft.

The ABS HSNC Rules presents the following equations for the calculations of the global loads acting on a twin hull vessel:

• Wave Induced Bending Moment Amidships: (ABS 3-2-1/3.1) 2 -3 Mws = -k1C1L B(Cb+0.7)x10 Sagging Moment 2 -3 Mwh = +k2C1L BCbx10 Hogging Moment

• Still Water Bending Moment: (ABS 3-2-1/3.1)

Msws = 0 Sagging Moment 2 Mswh = 0.375fpC1C2L B(Cb+0.7) Hogging Moment

• Slamming Induced Bending Moment: (ABS 3-2-1/1.1.2(d))

Msl = C3∆(1+ncg)(L-ls)

• Design Transverse Bending Moment: (ABS 3-2-1/3.3)

Mtb = K1∆Bcl(1+ncg)

• Design Torsional Moment: (ABS 3-2-1/3.3)

Mtt = K2∆L(1+ncg)

After defining all of these components for the global loading on the vessel, ABS also includes definitions for the combined, total moments acting on the hull girder that need to be considered for the structural design of the vessel. These combined moments are:

Mt = Mswh + Mwh Total Hogging Moment (ABS 3-2-1/1.1.2(e)) -Msws - Mws Total Sagging Moment Msl Slam Induced Bending Moment

As noted by the equations presented above, neither the still water nor the wave induced vertical moments include any terms for the speed or vertical acceleration of the craft, unlike all of the other moment expressions included by ABS. This implies that the values of these global moment components is independent of craft type and suggests that the vertical global bending moments will be the same for a given vessel regardless of whether it is to be defined as Naval Craft or Coastal Naval Craft. This is reflected in the moment calculations summarized below. All of the other moments include the consideration for the vertical acceleration of the craft and produce different values for slam induced, transverse bending and torsional moments acting on the vessel.

Table 5-1 and Table 5-2 summarize the global loads acting on the hull girder of the PacifiCat using the ABS High Speed Naval Craft Rules [1]. These two tables present the same results in Metric and English Units.

In no case do the survival loads exceed the operational loads. While this may seem counterintuitive it is easy to explain when the variables affected by these definitions are reviewed. As shown below in Figure 5-2, the two variables defined for the Operational and Survival conditions are Design Significant Wave Height, h1/3, and Speed, V. The change in these values and their effect on the structural design loads is reflected in the value for the design vertical acceleration, ncg, which then has a direct bearing on the global moment values calculated above. For the current situation involving the notations of Naval Craft and Coastal Naval Craft with a design speed of 37 knots, the following impacts to the design equations are noted. Also, as shown below, the value for ncg varies linearly with h1/3 while varying with the square of V. Therefore, for Naval Craft changing from operational to survival would see an increase of ncg as a function of h1/3 equal to (6/4) = 1.5 while for Coastal Naval Craft the effect of h1/3 is also seen to increase ncg by the ratio of (4/2.5) = 1.6. However, both of these increases are strongly overshadowed by the reducing effect resulting from the decrease in speed from 37 knots to 10 knots. The speed reduction would serve to reduce ncg for both Naval Craft and Coastal Naval Craft by the ratio of (10/37)2 = 0.073.

Table 5-1. ABS Global Hull Girder Loads for Naval & Coastal Naval Notations – Metric Units

Max Vertical SW Hogging WI Hogging SW Sagging WI Sagging Slam Induced Transverse Torsional Moment* kN - m kN - m kN - m kN - m kN - m kN - m kN - m kN - m Naval, 161,123 68,966 92,157 0 -115,601 101,539 127,636 273,143 Operational Naval, 161,123 68,966 92,157 0 -115,601 83,524 104,991 224,682 Survival Coastal, 161,123 68,966 92,157 0 -115,601 95,807 120,430 257,723 Operational Coastal, 161,123 68,966 92,157 0 -115,601 83,524 104,991 224,682 Survival Note: * The Maximum Vertical Moment is the worst-case absolute value moment comparing SW Hogging + WI Hogging and SW Sagging + WI Sagging where SW = Still Water and WI = Wave Induced.

Table 5-2. ABS Global Hull Girder Loads for Naval & Coastal Naval Notations – English Units

Max Vertical SW Hogging WI Hogging SW Sagging WI Sagging Slam Induced Transverse Torsional Moment* Lton-ft Lton-ft Lton-ft Lton-ft Lton-ft Lton-ft Lton-ft Lton-ft Naval, 53,052.8 22,708.3 30,344.4 0.0 -38,063.8 33,433.6 42,026.5 89,937.5 Operational Naval, 53,052.8 22,708.3 30,344.4 0.0 -38,063.8 27,501.8 34,570.3 73,980.8 Survival Coastal, 53,052.8 22,708.3 30,344.4 0.0 -38,063.8 31,546.3 39,653.8 84,860.1 Operational Coastal, 53,052.8 22,708.3 30,344.4 0.0 -38,063.8 27,501.8 34,570.3 73,980.8 Survival Note: * The Maximum Vertical Moment is the worst-case absolute value moment comparing SW Hogging + WI Hogging and SW Sagging + WI Sagging where SW = Still Water and WI = Wave Induced.

5.3.3 ABS Secondary Slam Loads

For a given ship and design speed, the most important variable in consideration of secondary slam loads is the vertical acceleration at the center of gravity, ncg. This is a critical variable for a number of the global loads shown above as well as all secondary slam loads. For preliminary design, this variable is presented in ABS 3-2-2/1.1 [1] and is calculated as:

2 2 12h1/ 3  V (N h Bw ) ncg = N 2  +1.0τ []50 − β cg  N h Bw  ∆

All variables are defined in the List of Symbols included in the Front Matter of this report. For quick reference, it is worth repeating that h1/3 is the Design Significant Wave Height and V is the speed of the vessel in knots. The values for ncg are developed using the input from ABS 3-2- 2/Table 1 [1] which defines criteria for Operational and Survival conditions for the various craft notations. This table is repeated below as Figure 5-2:

Operational Condition Survival Condition h1/3 V h1/3 V 2 1 3 Naval Craft 4 m (13 ft) Vm 6 m (20 ft) 10 knots 2 3 Coastal Naval Craft 2.5 m (8.5 ft) Vm 4 m (13 ft) 10 knots 2 3 Riverine Naval Craft 0.5 m (1.75 ft) Vm 1.25 m (4 ft) 10 knots Notes 1. Not to be taken less than L/12 2. Vm = maximum speed for the craft in the design condition specified in 3-2-2/1 3. This speed is to be verified by the Naval Administration

Figure 5-2. Design Significant Wave Heights, h1/3, and Speeds, V from ABS 3-2-1/Table 1

Using the input from this table and the associated vessel particulars, results in the following values for ncg for this design:

Naval Craft, Operational ⇒ ncg = 0.24 g’s Naval Craft, Survival ⇒ ncg = 0.02 g’s Coastal Naval Craft, Operational ⇒ ncg = 0.17 g’s Coastal Naval Craft, Survival ⇒ ncg = 0.02 g’s

ABS 3-2-2/3.1, 3.3 and 3.5 [1] provides equations for the determination of Bottom, Side and Transom, and Wet Deck Slamming, respectively. These equations are given as:

• 3.1.1 Bottom Slamming Pressure: (ABS 3-2-2/3.1)

  N1∆ 70 − β bx pbxx = []1 + nxx  Fd Lw N h Bw 70 − β cg 

• 3.3.1 Side and Transom Slamming Pressure: (ABS 3-2-2/3.3)

  N1∆ 70 − β sx psxx = []1 + nxx  Fd Lw N h Bw 70 − β cg 

• 3.5 Wet Deck or Cross Structure Slamming Pressure: (ABS 3-2-2/3.5)

pwd = 30N1 FD FIVVI (1 − 0.85ha / h1/ 3 )

In all these equations, nxx, is the vertical acceleration at section x – x of the ship which can be determined from the relationship:

nxx = ncgKv

Where Kv is the vertical acceleration distribution factor from ABS 3-2-2/Figure 7 [1], shown in Figure 5-3:

Figure 5-3. ABS Vertical Acceleration Distribution Factor KV, from ABS 3-2-2/Figure 7

FI, shown above, is the Wet Deck pressure distribution factor and is obtained from ABS 3-2- 2/Figure 9 [1] and shown below in Figure 5-4:

Figure 5-4. ABS Wet Deck Pressure Distribution Factor FI, from ABS 3-2-2/Figure 9

Based on all the input and equation information provided above, Table 5-4 provides the ABS slam load data for the Naval Craft in Operational and Survival conditions in Metric units. Table 5-5 provides the slam load data for the Coastal Naval Craft in Operational and Survival conditions in Metric units. Table 5-6 and Table 5-7 present the same information using English units of measure.

The same effect to the secondary slam loads is realized as the global bending moments, i.e., the survival loads are lower than the operational loads. The explanation is the same as that provided above.

NOTE TO READERS

The correlation between the “Location” references throughout the rest of this report and actual location along the ship length is shown below in Table 5-3.

Table 5-3. Correlation of Table Locations & Ship Frames

Location Frame Number Location Frame Number 1 88 (FP) 7 29.2 2 78.2 8 19.4 3 68.4 9 9.6 4 58.6 10 -0.2 (AP) 5 48.8 11 -10.0 6 39.0

Table 5-4. ABS Secondary Slam Load Pressures for Naval Craft Operational & Survival Conditions - Metric Units

All pressures are kN/m2

Naval Craft Operational Naval Craft Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 243.3 94.05 138.3 171.0 66.09 67.6 2 235.4 91.00 138.3 170.3 65.84 67.6 3 227.5 87.95 138.3 169.6 65.58 67.6 4 219.6 84.90 55.3 169.0 65.33 27.0 5 211.7 81.85 55.3 168.3 65.07 27.0 6 203.8 78.80 55.3 167.7 64.82 27.0 7 195.9 75.75 55.3 167.0 64.56 27.0 8 226.3 75.75 55.3 192.9 64.56 27.0 9 265.0 75.75 55.3 225.9 64.56 27.0 10 293.9 75.75 62.2 250.5 64.56 30.4 11 293.9 75.75 69.2 250.5 64.56 33.8

Table 5-5. ABS Secondary Slam Load Pressures for Coastal Naval Craft Operational & Survival Conditions - Metric Units

All pressures are kN/m2

Coastal Naval Craft Operational Coastal Naval Craft Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 220.3 85.15 33.9 171.0 66.09 37.4 2 214.7 82.99 33.9 170.3 65.84 37.4 3 209.1 80.83 33.9 169.6 65.58 37.4 4 203.5 78.67 13.6* 169.0 65.33 15.0 5 197.9 76.51 13.6* 168.3 65.07 15.0 6 192.3 74.35 13.6* 167.7 64.82 15.0 7 186.7 72.19 13.6* 167.0 64.56 15.0 8 215.7 72.19 13.6* 192.9 64.56 15.0 9 252.6 72.19 13.6* 225.9 64.56 15.0 10 280.1 72.19 15.3* 250.5 64.56 16.8 11 280.1 72.19 17.0* 250.5 64.54 18.7

*These slam loads are less than other design minimum loads that are typically applied to shell structure, i.e., 500 psf = 3.5 psi = 25.8 kN/m2 for the design of shell plate and stiffening.

Table 5-6. ABS Secondary Slam Load Pressures for Naval Craft Operational & Survival Conditions - English Units

All pressures are PSI

Naval Craft Operational Naval Craft Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 35.3 13.64 20.1 24.8 9.58 9.8 2 34.1 13.19 20.1 24.7 9.55 9.8 3 33.0 12.75 20.1 24.6 9.51 9.8 4 31.8 12.31 8.0 24.5 9.47 3.9 5 30.7 11.87 8.0 24.4 9.44 3.9 6 29.6 11.43 8.0 24.3 9.40 3.9 7 28.4 10.98 8.0 24.2 9.36 3.9 8 32.8 10.98 8.0 28.0 9.36 3.9 9 38.4 10.98 8.0 32.8 9.36 3.9 10 42.6 10.98 9.0 36.3 9.36 4.4 11 42.6 10.98 10.0 36.3 9.36 4.9

Table 5-7. ABS Secondary Slam Load Pressures for Coastal Naval Craft Operational & Survival Conditions - English Units

All pressures are PSI

Coastal Naval Craft Operational Coastal Naval Craft Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 31.9 12.35 4.9 24.8 9.58 5.4 2 31.1 12.03 4.9 24.7 9.55 5.4 3 30.3 11.72 4.9 24.6 9.51 5.4 4 29.5 11.41 2.0* 24.5 9.47 2.2* 5 28.7 11.09 2.0* 24.4 9.44 2.2* 6 27.9 10.78 2.0* 24.3 9.40 2.2* 7 27.1 10.47 2.0* 24.2 9.36 2.2* 8 31.3 10.47 2.0* 28.0 9.36 2.2* 9 36.6 10.47 2.0* 32.8 9.36 2.2* 10 40.6 10.47 2.2* 36.3 9.36 2.4* 11 40.6 10.47 2.5* 36.3 9.36 2.7*

*These slam loads are less than other design minimum loads that are typically applied to shell structure, i.e., 500 psf = 3.5 psi = 25.8 kN/m2 for the design of shell plate and stiffening.

5.4 DNV STRUCTURAL LOADS

In accordance with DNV the global hull girder and local slamming loads acting on a high-speed vessel are a function of its service restrictions and the type of craft.

5.4.1 DNV Service Restrictions and Vessel Types

An important consideration for the development of loads in accordance with DNV is the type and service of the vessel to be designed. The types of vessels include:

• Passenger • Car Ferry • Cargo • Crew • Yacht • Patrol • Naval

The areas of service of these vessels includes, see Figure 5-5:

• Unrestricted • Ocean • Offshore • Coastal • Inshore • Inland • Sheltered

As part of these definitions, DNV also includes service area restrictions, which relates to the distance from safe harbor that a vessel is allowed to operate during different times of the year. The service area restriction definitions allow an owner to design a vessel tailored to the environment expected for the operation of the vessel. The service area restrictions range from R0 to R6 and are shown in Figure 5-5 below, which is reprinted from DNV Part 1, Chapter 1, Section 2/401 [2]. Each of the service area restrictions requires the calculation for global loads and slamming loads. The values of various coefficients that are used for the load calculations have reduced values as the service area restrictions become more severe, i.e., the design loads decrease as the allowable, maximum distance from safe harbor decreases. This reduces the loads acting on the ship structure and the subsequent cost for the structural design and fabrication. Figure 5-5 summarizes the various service area restriction notations and defines the maximum distances from safe harbor, in nautical miles, that a vessel can operate for the given notation.

Table B1 Service restrictions, general Condition Notation Winter Summer Tropical Ocean None 1) 1) 1) Ocean R0 300 1) 1) Ocean R1 100 300 300 Offshore R2 50 100 250 Coastal R3 20 50 100 Inshore R4 5 10 20 Inland R5 1 2 5 Sheltered R6 0.2 0.3 0.5

Guidance Note:

1) Unrestricted service notation is not applicable to craft falling within the scope of the HSC Code, i.e., service and type Notations Passenger, Car Ferry or Cargo.

Figure 5-5. DNV Service Restrictions from DNV 1-1-2/401

As called out in Note 1 in Figure 5-5, the unrestricted service notation is not applicable to craft designed for the HSC Code. Therefore, it was necessary to check the requirements for Patrol and Naval craft to see if the criteria for either one of these classes allows for the unrestricted operation notation.

DNV Table F1 and Table F2, shown below in Figure 5-6, are from DNV Part 0, Chapter 5, Section 1 [2]. They imply that the unrestricted service notation may be available for both the Patrol and Naval craft notations.

Table F1 Overview of class notations Main class requirements Craft for special Special equipment and service systems Mandatory requirements Mandatory Optional requirements for all craft (military and requirements for each for special equipment merchant) craft type or features including Rules Pt. 1, Pt. 2, Pt. 3 Rules Pt. 5 naval performance and Pt.4 Rules Pt. 6 ? Patrol E0 1A1 Naval NAUT R0 HMON R1 ICS R2 ELT R3 NBC “unrestricted” N, SV, MV Abbreviations used are explained in Table F2 to F6. F 400 Main class notations (Pt. 1 to Pt. 5 of the rules)

401 The main class notations for naval surface craft are Explained in Table F2. Table F2 Main class notations for naval surface craft Class notation Description (See Pt.1, Pt. 2, Pt.3, Pt. 4 and Pt. 5) ? Construction symbol indicating that the craft is built under supervision by the Society. 1A1 Mandatory minimum requirements to accommodate (Pt. 1 to Pt.4) for naval operations with respect to:

- freeboard, stability and watertight integrity - structural strength - propulsion system - electrical power supply - steering, navigation and communication - fire safety - equipment - accommodation and lifesaving equipment. “Unrestricted” Unlimited service worldwide when no service restriction is given. R0 to R3 Service restriction specifies maximum distance from safe place of refuge/harbour/anchorage. Naval Mandatory minimum requirements to accommodate (Pt. 5 Ch. 7) for naval operations with respect to:

- wave loads - stability and watertight integrity - loads from weapon systems - survivability - damage resistance

to the hull, machinery and systems

The requirements can be n the form of additions and exemptions to Pt. 1, Pt. 2, Pt. 3 and Pt. 4

Figure 5-6. DNV Patrol & Naval Craft Notations from DNV 0-5-1

The Patrol Craft criteria are contained in DNV Part 5, Chapter 6. Section 1/301 [2] of this portion of the rules states:

“Craft with the class notation Patrol will be assigned one of the service restrictions R0, R1, R2, or R3.”

This provides a concrete definition that Patrol craft cannot be granted an unrestricted notation without seeking a deviation from the rules. Since that is not the intent of this project it became necessary to investigate the Naval Craft criteria to determine if unrestricted notation is allowed within the rules for these craft.

The Naval Craft criteria are contained in DNV Part 5, Chapter 7 [2]. Table A1 from Section 3/A201, shown below as Figure 5-7 provides the definition that confirms that Naval Surface Craft can be designed for unrestricted operation.

Table A1 Acceleration factor fg Type and service Service area restriction notation notation None R0 R1 R2 R3 Naval 8 7 5 3 1 None = unrestricted service

Guidance note: Vertical design acceleration acg is to be considered as a design Parameter used for calculation of local and global loads and for Specification of operational restrictions for the craft.

Figure 5-7. DNV Acceleration factor fg for Naval Surface Craft from DNV 5-7-3/A201

It is particularly important to recognize two impacts of Table A1, Figure 5-7:

1. It does confirm the allowance of Naval craft to be designed for unrestricted notation.

2. The values given in Table A1 are for the acceleration factor, fg, which is used to calculate acg, the design vertical acceleration at the center of gravity of the vessel, which is used as a variable for all slam load and global hull girder load calculations. The value of fg = 8 is required for unrestricted notation. The value of fg = 1 was used for the original R4 PacifiCat design. The value used for the original PacifiCat design was taken from DNV Part 3, Chapter 1, Section 2 B/201 Table B1 [2] as shown below in Figure 5-8.

Table B1 Acceleration factor fg Type and service Service area restriction notation notation R0 R1 R2 R3 R4 R5-R6

Passenger 1) 1 1 1 1 0.5 Car Ferry 1) 1 1 1 1 0.5 Cargo 4 3 2 1 1 0.5 Patrol 7 5 3 1 1 0.5 Yacht 1 1 1 1 1 0.5 1) Service area restriction R0 is not available for class notations Passenger and Car Ferry.

Figure 5-8. DNV Acceleration factor fg for Other Service Types from DNV 3-1-2 B/201

The increase of fg from 1 to 8 plays a very significant role increasing the loads required to convert the vessel in accordance with the DNV HSLC&NSC criteria. The equation for acg is presented in various locations of the DNV rules for consideration of commercial and naval craft. Regardless, the same equation is used for the R4, R1 and unrestricted calculations in this project and is given below as:

 V  3.2  a =   f g (m/s2) cg   0.76  g 0  L  L 

V Where: need not be taken greater than 3.0 L

V, L defined in the List of Symbols 2 g0 = 9.81 m/s fg = Acceleration factor discussed above acg = Vertical design acceleration

For the Operational condition using V = 37 knots, L = 96 meters and V/√L ≤ 3.0, results in:

2 acg = 2.8 m/s for Car Ferry, R4 notation, fg =1 2 acg = 15.1 m/s for R1, fg = 5 2 acg = 23.5 m/s for Naval Surface Craft, Unrestricted, fg = 8

A requirement in DNV Part 3, Chapter 1, Section2/B201 [2] states that acg cannot be taken as less than 1g0 for service notations R0 – R4. This redefines the value shown above from acg = 2.8 2 2 m/s to acg = 9.8 m/s for the R4 notation. Regardless, this represents an increase of approximately 240% in a variable that is directly used in the calculation of all hull girder and slam loads required for the structural design of the vessel in the operational mode.

In the survival condition, V = 10 knots is substituted above, for comparison to ABS.

For the Survival condition, V = 10 knots, L = 96 meters results in:

2 acg = 1.0 m/s for Car Ferry, R4 notation, fg =1 2 acg = 5.0 m/s for R1, Unrestricted, fg = 5 2 acg = 8.0 m/s for Naval Surface Craft, Unrestricted, fg = 8

2 All of these values default to acg = 9.81 m/s .

5.4.2 DNV Global Loads

As stated above, the Naval Surface Craft design criteria are presented in DNV HSLC & NSC Part 5, Chapter 7 [2]. For calculation of the Midship vertical wave bending moment DNV 5-7- 3/B 201 refers to the earlier section of the rules that deals with all vertical moment calculations, DNV Part 5, Chapter 7, Section 3 and Part 3, Chapter 1. Most of the actual load calculations appear in Part 3, Chapter 1. The most important aspect from DNV 5-7-3 is the calculation for acg, the design vertical acceleration, which, as stated above, uses a value of fg = 8 for Naval 2 Surface Craft, resulting in the value of acg = 23.5 m/s .

The DNV HSLC & NSC Rules presents the following equations for the calculations of the global loads acting on a twin hull vessel:

2 • Mtot hog = Msw +0.19CwL (BwL2 + k2 Btn)CB (DNV 3-1-3/A 503) 2 • Mtot sag = Msw + 0.14CwL (BwL2 + k3 Btn) (CB + 0.7) (DNV 3-1-3/A 503)

• Msw = Still water bending moment (DNV 3-1-3/A 503) = 0.5∆L in hogging, if not known = 0 in sagging, if not known

The slam induced bending moments in DNV are generated from two different conditions:

• Crest Landing

∆  ls  M B = ()g 0 + acg ew −  (DNV 3-1-3/A 200) 2  4 

• Hollow Landing

∆ M = ()g + a ()e − e (DNV 3-1-3/A 300) B 2 0 cg r w

The transverse hull girder bending moment is to be taken as the worst of the following two conditions:

 a  M M 1 cg  (DNV 3-1-3/B 202) s = so  +   g 0 

M s = M so + Fy ()z − 0.5T (DNV 3-1-3/B 202)

DNV defines pitch connecting and torsional moments in accordance with DNV 3-1-3/B 301/Figure 7:

The pitch connecting moment is determined as:

∆a L M = cg (DNV 3-1-3/B 301) p 8

The torsional moment is defined as:

∆a b M = cg (DNV 3-1-3/B 400) t 4

DNV 3-1-3/A 800 [2] requires the following hull girder load combinations be considered:

• 80% longitudinal bending and shear + 60% torsion • 60% longitudinal bending and shear + 80% torsion • 70% transverse bending + 100% pitch connecting • 100% transverse bending + 70% pitch connecting

Similar to the ABS load calculations, the DNV vertical bending moments for wave induced and still water do not include any effect of vessel speed or vertical acceleration. All other global moment loads do include an effect from vertical acceleration of the vessel.

Table 5-8 (Metric units) and Table 5-9 (English units), present the DNV global moments required for the R1 and Unrestricted service notations for the vessel in accordance with the DNV HSLC&NSC Rules.

2 In Table 5-8, the Crest Landing, R1 Survival Moment (acg =9.81 m/s ), is greater than the Crest 2 Landing, R1 Operational Moment, (acg = 15.1 m/s ) and the Hollow Landing, R1 Operational

2 Moment (acg = 15.1 m/s ), is greater than the Hollow Landing, Unrestricted Operational Moment 2 (acg = 23.5 m/s ) because of the manner in which these values are calculated. The equations for Hollow and Crest Landing require definition of ew, ls, and er, which in turn require the definitions for AR and bs. These relationships are presented below:

ew = one half the distance from the LCG of the fore half body to the LCG of the aft half body of the vessel, in m = 0.25L for crest landing if not known (0.2L for hollow landing)

er = mean distance from the center of the AR/2 end areas to the vessels LCG, m. (Refer to sketch for hollow landing.)

ls = longitudinal extension of the slamming reference area given as:

AR ls = bs

where bs is the breadth of the slamming reference area.

 a  1+ 0.2 cg   g  A = k∆  0  (m2) R T

where k = 0.7 for crest landing and 0.6 for hollow landing.

Investigation shows that as acg increases, so do the values of AR and ls. Therefore, the value of Crest landing decreases as acg increases because the term (ew – ls/4) decreases.

Similarly, the term (er – ew) for hollow landing decreases as the value of acg increases because er decreases as acg and AR increase.

Table 5-8. DNV Global Hull Girder Loads for R1 & Unrestricted Notations - Metric Units

MaxVert SW WI SW WI Crest Hollow Transverse Pitch Torsional Moment* Hogging Hogging Sagging Sagging Landing Landing kN-m Connecting kN-m kN-m kN-m kN-m kN-m kN-m kN-m kN-m kN-m Unrestricted 245,774 90,835 122,825 0 245,774 120,939 169,564 130,527 533,093 241,633 Operational Unrestricted 245,774 90,835 122,825 0 245,774 118,316 165,031 76,901 222,547 100,873 Survival R1 245,774 90,835 122,825 0 245,774 113,914 177,062 96,006 333,183 151,021 Operational R1 245,774 90,835 122,825 0 245,774 118,316 165,031 76,901 222,547 100,873 Survival Note: * The Maximum Vertical Moment is the worst-case absolute value moment comparing SW Hogging + WI Hogging and SW Sagging + WI Sagging where SW = Still Water and WI = Wave Induced.

Table 5-9. DNV Global Hull Girder Loads for R1 & Unrestricted Notations - English Units

Max Vert SW WI SW WI Crest Hollow Transverse Pitch Torsional Moment* Hogging Hogging Sagging Sagging Landing Landing Lton-Ft Connecting Lton-Ft Lton-Ft Lton-Ft Lton-Ft Lton-Ft Lton-Ft Lton-Ft Lton-Ft Lton-Ft Unrestricted 80,925.7 29,909.1 40,442.4 0 80,925.7 39,821.4 55,832.1 42,978.5 175,530.9 79,562.2 Operational Unrestricted 80,925.7 29,909.1 40,442.4 0 80,925.7 38,957.8 54,339.6 25,321.1 73,277.8 33,214.3 Survival R1 80,925.7 29,909.1 40,442.4 0 80,925.7 37,508.3 58,301.0 31,611.8 109,706.7 49,726.5 Operational R1 80,925.7 29,909.1 40,442.4 0 80,925.7 38,957.8 54,339.6 25,321.1 73,277.8 33,214.3 Survival Note: * The Maximum Vertical Moment is the worst-case absolute value moment comparing SW Hogging + WI Hogging and SW Sagging + WI Sagging where SW = Still Water and WI = Wave Induced.

5.4.3 DNV Secondary Slamming Loads

Similar to the global loads, DNV 5-7-3 [2] refers to DNV 3-1 [2] for the calculation of secondary slam loads. More specifically, the bottom slamming and bow impact pressures are to be obtained from DNV 3-1-2/C 200 and C 300 [2]. The Wet Deck slamming loads are to be obtained from DNV 3-1-2/C 400 [2]. The vertical acceleration, acg, to be used in those calculations is obtained from the Naval Surface Craft requirements in DNV 5-7-3 [2] for the unrestricted notation. For service restriction R1 the vertical acceleration is obtained from DNV 3-1-2/B 200 [2].

The bottom slamming pressure is calculated as:

0.3  ∆   50 − β  P =1.3k T 0.7  x a (DNV 3-1-2/C 200) sl l   O   cg  nA   50 − β cg 

The forebody side and bow impact pressures are calculated from DNV 3-1-2/C 300 as:

2 0.7LC C  V 2.1a V  x  P = L H 0.6 + 0.4 sin γ cos(90 − α) + 0 0.4 + 0.6 sin(90 − α) − 0.4 sl 0.3   A  L C B L  L 

The Wet Deck slamming pressures are calculated using:

0.3  ∆   H   C  Psl = 2.6kt   acg 1 −  (DNV 3-1-2/C 400)  A   H L 

Table 5-10 and Table 5-11 present the DNV R1 and Unrestricted slam loads, respectively, in Metric notation. Table 5-12 and Table 5-13 present the same information in the English system of units.

Table 5-10. DNV Secondary Slam Load Pressures for R1 Notation Operational & Survival Conditions - Metric Units

All pressures are kN/m2

R1 Operational R1 Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 375.8 103.6 164.0 251.0 103.6 55.8 2 375.8 97.1 164.0 251.0 97.1 55.8 3 375.8 90.6 164.0 251.0 90.6 55.8 4 375.8 84.1 164.0 251.0 84.1 55.8 5 375.8 77.6 82.0 251.0 77.6 27.9 6 375.8 71.2 82.0 251.0 71.2 27.9 7 338.3 71.2 82.0 225.9 71.2 27.9 8 393.9 71.2 82.0 263.1 71.2 27.9 9 448.6 71.2 82.0 299.6 71.2 27.9 10 451.0 71.2 82.0 301.2 71.2 27.9 11 375.8 71.2 82.0 251.0 71.2 27.9

Table 5-11. DNV Secondary Slam Load Pressures for Unrestricted Notation Operational & Survival Conditions - Metric Units

All pressures are kN/m2

Unrestricted Operational Unrestricted Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 601.3 103.6 262.4 251.0 103.6 89.3 2 601.3 97.1 262.4 251.0 97.1 89.3 3 601.3 90.6 262.4 251.0 90.6 89.3 4 601.3 84.1 262.4 251.0 84.1 89.3 5 601.3 77.6 131.2 251.0 77.6 44.6 6 601.3 71.2 131.2 251.0 71.2 44.6 7 541.2 71.2 131.2 225.9 71.2 44.6 8 630.2 71.2 131.2 263.1 71.2 44.6 9 717.7 71.2 131.2 299.6 71.2 44.6 10 721.6 71.2 131.2 301.2 71.2 44.6 11 601.3 71.2 131.2 251.0 71.2 44.6

Table 5-12. DNV Secondary Slam Load Pressures for R1 Notation Operational & Survival Conditions - English Units

All pressures are PSI

R1 Operational R1 Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 54.5 15.0 23.8 36.4 15.0 8.1 2 54.5 14.1 23.8 36.4 14.1 8.1 3 54.5 13.1 23.8 36.4 13.1 8.1 4 54.5 12.2 23.8 36.4 12.2 8.1 5 54.5 11.3 11.9 36.4 11.3 4.0 6 54.5 10.3 11.9 36.4 10.3 4.0 7 49.1 10.3 11.9 32.8 10.3 4.0 8 57.1 10.3 11.9 38.1 10.3 4.0 9 65.0 10.3 11.9 43.4 10.3 4.0 10 65.4 10.3 11.9 43.7 10.3 4.0 11 54.5 10.3 11.9 36.4 10.3 4.0

Table 5-13. DNV Secondary Slam Load Pressures for Unrestricted Notation Operational & Survival Conditions - English Units

All pressures are PSI

Unrestricted Operational Unrestricted Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 87.2 15.0 38.0 36.4 15.0 12.9 2 87.2 14.1 38.0 36.4 14.1 12.9 3 87.2 13.1 38.0 36.4 13.1 12.9 4 87.2 12.2 38.0 36.4 12.2 12.9 5 87.2 11.3 19.0 36.4 11.3 6.5 6 87.2 10.3 19.0 36.4 10.3 6.5 7 78.5 10.3 19.0 32.8 10.3 6.5 8 91.4 10.3 19.0 38.1 10.3 6.5 9 104.1 10.3 19.0 43.4 10.3 6.5 10 104.6 10.3 19.0 43.7 10.3 6.5 11 87.2 10.3 19.0 36.4 10.3 6.5

5.4.4 Direct Comparison of ABS and DNV Hull Girder and Secondary Slam Loads

The following tables present the respective hull girder and slamming loads from ABS and DNV in the same tables for ease of comparison.

Table 5-14 compares the ABS and DNV global loads. It only includes the ABS Naval and DNV Unrestricted classification loads. It does not include the ABS Coastal Naval and DNV R1 Service Restriction loads. The values shown in Table 5-14 address the loads that represent the final conversion objective of the project.

Table 5-15 and Table 5-16 are copies of Table 5-4 and Table 5-11, respectively. They present the ABS and DNV slam loads for the ABS Naval and DNV Unrestricted classifications. Similar to the global loads, the comparison tables are only presented for the final objective design loads of this project.

Table 5-14. Comparison of ABS & DNV Global Hull Girder Loads - Metric Units

Max Vertical Transverse Torsional Slam Pitch Crest Hollow Moment* kN - m kN - m Induced Connecting Landing Landing kN - m kN - m kN-m kN-m kN-m ABS Naval, 161,123 127,636 273,143 101,539 NA NA NA Operational ABS Naval, 161,123 104,991 224,682 83,524 NA NA NA Survival DNV 245,774 130,527 241,633 NA 533,093 120,939 169,564 Unrestricted Operational DNV 245,774 76,901 100,873 NA 222,547 118,316 165,031 Unrestricted Survival Note: * Maximum value of Wave Induced plus Still Water, hogging and sagging conditions.

Table 5-15. ABS Secondary Slam Load Pressures for Naval Craft Operational & Survival Conditions - Metric Units All pressures are kN/m2 Naval Craft Operational Naval Craft Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 243.3 94.05 138.3 171.0 66.09 67.6 2 235.4 91.00 138.3 170.3 65.84 67.6 3 227.5 87.95 138.3 169.6 65.58 67.6 4 219.6 84.90 55.3 169.0 65.33 27.0 5 211.7 81.85 55.3 168.3 65.07 27.0 6 203.8 78.80 55.3 167.7 64.82 27.0 7 195.9 75.75 55.3 167.0 64.56 27.0 8 226.3 75.75 55.3 192.9 64.56 27.0 9 265.0 75.75 55.3 225.9 64.56 27.0 10 293.9 75.75 62.2 250.5 64.56 30.4 11 293.9 75.75 69.2 250.5 64.56 33.8

Table 5-16. DNV Secondary Slam Load Pressures for Unrestricted Notation Operational & Survival Conditions - Metric Units All pressures are kN/m2 Unrestricted Operational Unrestricted Survival Location Bottom Side & Transom Wet Deck Bottom Side & Transom Wet Deck Slamming Slamming Slamming Slamming Slamming Slamming 1 601.3 103.6 262.4 251.0 103.6 89.3 2 601.3 97.1 262.4 251.0 97.1 89.3 3 601.3 90.6 262.4 251.0 90.6 89.3 4 601.3 84.1 262.4 251.0 84.1 89.3 5 601.3 77.6 131.2 251.0 77.6 44.6 6 601.3 71.2 131.2 251.0 71.2 44.6 7 541.2 71.2 131.2 225.9 71.2 44.6 8 630.2 71.2 131.2 263.1 71.2 44.6 9 717.7 71.2 131.2 299.6 71.2 44.6 10 721.6 71.2 131.2 301.2 71.2 44.6 11 601.3 71.2 131.2 251.0 71.2 44.6

5.5 LOADS USED FOR THE DESIGN OF THE ORIGINAL PACIFICAT

The original design for the PacifiCat ferries was done using the DNV HSLC & NSC Rules [2] with an R4 service restriction for a car ferry. All the local slamming and global load calculations were developed using the same equations presented above with certain coefficients significantly reduced for the R4 notation compared to the unrestricted values used above. In particular, the two variables that have the most immediate impact are design vertical acceleration, acg and the wave coefficient, Cw. These values for R4 and unrestricted usage are:

2 acg = 9.8 m/s R4 Car Ferry 2 acg = 23.5 m/s Unrestricted Naval Craft

Cw = 4.61 R4 Car Ferry Cw = 7.68 Unrestricted Naval Craft

Table 5-17 and Table 5-18 present the DNV hull girder and slam loads, respectively using the Metric system of measure. Table 5-19 and Table 5-20 present the same information using the English system of notation. These can only be considered as the preliminary design, rule-book based load values used for the design of the PacifiCat. To date, it has not been possible to obtain the actual design loads from the builder and so the values presented below can be used for comparison.

Table 5-17. DNV Rule Book Global Hull Girder Loads for PacifiCat R4 Notation - Metric Units

Max Vert SW WI SW WI Crest Hollow Transverse Pitch Torsional Moment* Hogging Hogging Sagging Sagging Landing Landing kN-m Connecting kN-m kN-m kN-m kN-m kN-m kN-m kN-m kN-m kN-m R4 165,031 90,835 158,218 0.0 137,065 118,315 165,031 76,900 222,547 100,873

Note: * The Maximum Vertical Moment is the worst-case absolute value moment comparing ⏐SW Hogging + WI Hogging⏐ and ⏐SW Sagging + WI Sagging⏐ where SW = Still Water and WI = Wave Induced.

Table 5-18. DNV Rule Book Secondary Slam Load Pressures for PacifiCat R4 Notation

All pressures are kN/m2

R4 Location Bottom Side & Transom Wet Deck Slamming Slamming Slamming 1 251.0 70.0 32.8 2 251.0 66.1 32.8 3 251.0 62.2 32.8 4 251.0 58.3 32.8 5 251.0 54.4 16.4 6 251.0 50.5 16.4 7 225.9 50.5 16.4 8 263.1 50.5 16.4 9 299.6 50.5 16.4 10 301.2 50.5 16.4 11 251.0 50.5 16.4

Table 5-19. DNV Rule Book Global Hull Girder Loads for PacifiCat R4 Notation - English Units

Note: * The Maximum Vertical Moment is the worst-case absolute value moment comparing ⏐SW Hogging + WI Hogging⏐ and ⏐SW Sagging + WI Sagging⏐ where SW = Still Water and WI = Wave Induced.

Table 5-20. DNV Rule Book Secondary Slam Load Pressures for PacifiCat R4 Notation

All pressures are PSI

R4 Location Bottom Side & Transom Wet Deck Slamming Slamming Slamming 1 36.4 10.1 4.8 2 36.4 9.6 4.8 3 36.4 9.0 4.8 4 36.4 8.5 4.8 5 36.4 7.9 2.4 6 36.4 7.3 2.4 7 32.8 7.3 2.4 8 38.1 7.3 2.4 9 43.4 7.3 2.4 10 43.7 7.3 2.4 11 36.4 7.3 2.4

5.6 LOADS DUE TO PAYLOAD OF MILITARY VEHICLES

Discussion presented below uses the English system of units, inches & pounds, for all tire and vehicle data.

One of the critical loads to be considered for the structural modifications required for the conversion of the vessel are the tire footprint loads associated with the military vehicles. Typical vehicle deck structure is checked against the matrix of vehicles scheduled to access the deck and the worst footprint is used to design the deck plate and stiffening. In the case of extreme loads that may only result from a few select vehicles, it is standard practice to reinforce a portion of the deck as necessary to accommodate these loads and require that the governing vehicle park in the reinforced area. Of course, all deck structure leading to the reinforced area would also have to be reinforced to support the vehicle as it transits to it designated area. The reinforcement of the travel lanes may not be as demanding because such transit will occur with the ship pierside and the design vertical acceleration will reflect static 1g with no increase from ship motion effects, i.e., nxx = 0.

A typical vehicle footprint is shown in Figure 5-9. Other footprints are shown in Appendix C.

Figure 5-9. Typical Tire Footprint for Vehicle Deck Loading Data

Unfortunately, it was not possible to find all this footprint data for the MEU loadout selected for the conversion. Therefore, various approximations were made to estimate the footprints and associated tire pressures with the MEU loadout. The estimates are based on typical vehicle information used for sealift programs and originate from the technical manuals of the United States Marine Corps as well as other sources of information.

Assessment of the deck structure subjected to the vehicle loads was undertaken using both the ABS and DNV criteria. Both ABS and DNV present design criteria that directly addresses deck structure subjected to wheel loads.

5.6.1 Investigation of Tire Footprints on Deck Structure

The typical structural analysis of vehicle handling decks will investigate vehicles and their tires oriented in both the transverse and longitudinal direction, defining the more severe of the two conditions as the design governing criteria. The PacifiCat has a relatively long, narrow vehicle deck conducive to longitudinal travel for the vehicles. Also, it is not required that vehicles turn for off-loading, they can proceed “straight ahead” to off load at the end of the ship opposite from that which they entered due to the bow and stern access available on this vessel. In addition, the longitudinal stiffener spacing of the vehicle deck is relatively tight, either 210 mm or 200 mm, and the following discussion addresses this arrangement

The Main Vehicle Deck of the PacifiCat is fabricated using two different extrusions, a heavier extrusion from ship centerline to 3375 mm off centerline, P/S, and a lighter extrusion that covers the rest of the deck. Some basic characteristics of these two extrusions are summarized below:

Plate Thickness Stiffener Spacing Stiffener Depth (mm) (mm) (mm) Heavy Extrusion 9.8 210 140 Light Extrusion 8.0 200 103

The transverse web frame spacing is 1200 mm throughout the entire Main Vehicle Deck. This results in two similar deck panels that may require investigation subjected to vehicle tire footprint loads. These are shown schematically in Figure 5-10 as:

t = 9.8 mm = 0.389 in t = 8.0 mm Longitudinal 1200 mm = 0.315 in direction 47.24 in

210 mm 200 mm 8.27 in 7.87 in Heavy Extrusion Light Extrusion

Figure 5-10. Schematic Representation of Heavy & Light Deck Extrusions

As seen in Appendix C, most of the tire footprints have a minimum dimension that exceeds the stiffener spacing of these extrusions. This has some interesting implications regarding the assumptions inherent in the required plate thickness equations of ABS and DNV and further discussion on this issue is provided below. Also, it was not possible to gather all the tire footprint data for all the vehicles contained in the chosen load-out. The only vehicle for which this is thought to be a concern is the 25,000 pound forklift truck, shown below in Table 5-23. Realizing that the forklift truck will only be stowed and not operational reduces the concern regarding this vehicle since most forklift trucks only present design governing wheel loads when they are carrying a maximum payload and their front axle is carrying its maximum design load.

5.6.2 Vehicle Data – Tire Footprints

The typical requirement for the design of deck structure subjected to wheel loads is knowledge of both the load and the footprint associated with the tire or track load of the vehicles. No single source of information was found that provided this information for the current project. Data was gathered from earlier Sealift projects, an MTVR study (Medium Tactical Vehicle Replacement) [5] and Globalsecurity.org. None of these sources was able to provide exact data for any of the vehicles in the proposed loadout. Estimates using the available data were made to assess the impact of the military vehicle payload on the existing deck structure in accordance with the procedure discussed below.

It was the intent of this project to have footprint data for all of the vehicles in the proposed loadout. This was severely complicated by the lack of required data for vehicles. As work progressed, it became apparent that the original list of vehicles could be broken into three categories based on the data that became available:

1. High Confidence Data for Vehicles, Table 5-22, – This is a list of vehicles and associated footprint data that has a high degree of confidence. The information presented in Table 5-22 forms the baseline for the calculations determining the effect to deck structure to accommodate the MEU loadout. 2. Lower Confidence Data for Potentially Critical Vehicles, Table 5-23, – This is a list of vehicles that could govern the design of deck structure but for which very little direct information was available. These vehicles and the data assumed for their footprint is provided in Table 5-23. Estimates on footprint size and load were based on data from other, similar vehicles, such as those in Table 5-22. 3. Lower Confidence Data for Non-Critical Vehicles, Table 5-24, – There are a number of vehicles which, based on intuition and other calculations, will not govern the design of deck structure but also had very little direct information available. The appropriate data for these vehicles is included in Table 5-24 but no calculations will be required for these vehicles.

The data in Table 5-22, Table 5-23 and Table 5-24 is presented in English units only. This is raw data, unlike the calculated data reflecting ABS and DNV loads, which can be calculated in either English or metric units for both rule sets. It was considered appropriate to leave the raw data in its original units.

All of the vehicles included in the original table for the proposed loadout are included in one of the three tables shown below. The original table (Table 2-1) is presented below, in Table 5-21, for ease of reference.

Table 5-21. Notional Vehicle Load for Conversion Vessel

Table 5-22. Vehicle Footprint Data used for Deck Structural Requirements (High Confidence)

Vehicle Total Weight No Max Tire Footprint Deck Load Source of data (LBS) of Tires Tire/Track (IN x IN) (PSI) Load (LBS) Armored Combat Excavator 36,000 2 tracks 18,000 lb/track 180x15 6.67 Sealift (Fig A-5) MK-48 LVS, Front Power Unit 25,300 4 – 16R21 6830/tire 16x27 15.8 Globalsecurity.org Trailer, Cargo 3/4 T (M101A1) 1850 2 925 7x12 11.0 Globalsecurity.org Truck Ambulance 2 Litter 6000 4 – 37x12.5R- 1600 12.5x14 9.2 Globalsecurity.org (HMMWV) 16.5 Truck 7-T, MTVR 36,000 6 – 16R20 6100 16x25 15.3 MTVR data Truck 7-T M927, Extended Bed 37,000 6 – 4 rear are 6100 16x25 15.3 MTVR data 16R20 Truck Tow Carrier, HMMWV 7200 4 – 37x12.5R- 2000 12.5x14 11.4 Globalsecurity.org 16.5 Truck, Multi Purpose M998, 6500 4 – 37x12.5R- 1700 12.5x14 9.7 Globalsecurity.org HMMV 16.5 Truck, Avenger/Claws, HMMWV 7200 4 – 37x12.5R- 2000 12.5x14 11.4 Globalsecurity.org 16.5 Truck, Army Carr, HMMWV 7000 4 – 37x12.5R- 1950 12.5x14 11.1 Globalsecurity.org 16.5 Truck, Light Strike Vehicle (LSV) 4500 4 1200 9x9 14.8 Sealift (Fig A-1) 155MM Howitzer 9000 8 1200 8x12 12.5 Globalsecurity.org LAV Anti Tank (AT) 24,850 8 3299 22x11 13.6 Sealift (Fig A-2) LAV C2 26,180 8 3475 22x11 14.4 Sealift (Fig A-2) LAV Assault 25MM 24,040 8 3191 22x11 13.2 Sealift (Fig A-2) LAV Logistics (L) 28,200 8 3743 22x11 15.5 Sealift (Fig A-2) LAV, Mortar 23,200 8 3080 22x11 12.7 Sealift (Fig A-2) LAV, Maintenance Recovery 28,400 8 3770 22x11 15.6 Sealift (Fig A-2)

Table 5-23. Vehicle Footprint Data (Low Confidence – Potential Design Governing)

Vehicle Total Weight No Max Tire Footprint Deck Load Source of data (LBS) of Tires Tire/Track (IN x IN) (PSI) Load (LBS) AN/MLQ-36 28,000 AN/MRC-138B 6200 AN/MRC-145 6200 Truck, Forklift 25,600 TBD TBD TBD TBD Truck, Forklift 11,080 TBD TBD TBD TBD Tram 35,465 6 – 16R21 5911/tire 16x27 13.7 Container, Quadruple 5000 Trailer, Cargo M105 6500 Trailer, MK-14 16,000 Truck, 7-Ton Dump 31,888 6 – 16R20 4234 16x25 10.6 Assume MTVR Maintenance Van 10,000

Table 5-24. Vehicle Footprint Data (Low Confidence – Non-Design Governing)

Vehicle Total Weight No Max Tire Footprint Deck Load Source of data (LBS) of Tires Tire/Track (IN x IN) (PSI) Load (LBS) Chassis, Trailer 3/4 T 1840 2 920 7x12 11.0 Chassis, Trailer, Gen purp M353 2720 2 1360 7x12 16.2 Trailer, Tank Water 400 Gallon 2530 2 1265 7x12 15.1

5.6.3 Deck Structure Required – ABS HSNC Rules

Section 3-2-3/1.9 of the ABS HSNC Rules [1] addresses “Decks Provided for the Operation or Stowage of Vehicles.” It presents the following equations for deck thickness requirements in metric and English consideration:

βW ()1 + 0.5n βW (1 + 0.5n ) t = xx mm t = xx in 1000σ a σ a

Where: W = static wheel load in kN (lbf) nxx = average vertical acceleration at the location under consideration as defined in ABS 3-2-5/1.1 (misprint in HSNC – should actually read 3-2-2/1.1) β = as given in ABS 3-2-3/Figure 1, which is presented below as Figure 5-11 2 2 σa = design stress for decks, N/mm , (kgf/mm , psi), as given in ABS 3-2-3/Table 2, presented below as Figure 5-12

FIGURE 1 Values for β

b l

B/s l/s = 1 l/s = 1.4 l/s ≥ 2 a/s 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.8 1.2 1.4 0 0.4 0.8 1.2 1.6 2 0 1.82 1.38 1.12 0.93 0.76 2.00 1.55 1.12 0.84 0.75 1.64 1.20 0.97 0.78 0.64 0.2 1.82 1.28 1.08 0.90 0.76 0.63 1.78 1.43 1.23 0.95 0.74 0.64 1.73 1.31 1.03 0.84 0.68 0.57 0.4 1.39 1.07 0.84 0.72 0.62 0.52 1.39 1.13 1.00 0.80 0.62 0.55 1.32 1.08 0.88 0.74 0.60 0.50 0.6 1.12 0.90 0.74 0.60 0.52 0.43 1.10 0.91 0.82 0.68 0.53 0.47 1.04 0.90 0.76 0.64 0.54 0.44 0.8 0.92 0.76 0.62 0.51 0.42 0.36 0.90 0.76 0.68 0.57 0.45 0.40 0.87 0.76 0.63 0.54 0.44 0.38 1 0.76 0.63 0.52 0.42 0.35 0.30 0.75 0.62 0.57 0.47 0.38 0.33 0.71 0.61 0.53 0.45 0.38 0.30

Note: s = spacing of deck beams or deck longitudinals in mm (in.)

l = length of plate panel in mm (in.)

a = wheel imprint dimension, in mm (in.), parallel to the shorter edge, s, of the plate panel, and in general the lesser wheel imprint dimension

b = wheel imprint dimension, in mm (in.), parallel to the longer edge, l, of the plate panel, and in general the longer wheel imprint dimension

Figure 5-11. Aspect Ratio Data for Design of Wheel Loaded Deck Plate from ABS 3-2-3/Figure 1

TABLE 2 Design Stress, σa, Aluminum and Steel

(1) Location Design Stress, σa (2) Bottom Shell Slamming Pressure 0.90σy Hydrostatic Pressure 0.55σy

Water Jet Tunnels Slamming Pressure 0.60σy Hydrostatic Pressure 0.55σy

Side Shell Below Bulkhead Deck Slamming Pressure 0.90σy Hydrostatic Pressure 0.55σy

Above Bulkhead Deck Slamming Pressure 0.90σy (i.e., foc’sles) Hydrostatic Pressure 0.55σy Deck Plating Strength Deck 0.60σy Lower Decks/Other Decks 0.60σy Wet Decks 0.90σy Superstructure & Deckhouse Decks 0.60σy Bulkheads Deep Tank 0.60σy Watertight 0.95σy (3) Superstructure aft of 0.25L Front, Sides, Ends, Tops 0.60σy from F.P. & Deckhouses

Notes: 2 2 1 σy = yield strength of steel or of welded aluminum in N/mm (kgf/mm , psi), but not to be taken greater than 70% of the ultimate strength of steel or welded aluminum. 2 The design stress for bottom shell plates under slamming pressure may be taken as σy for plate outside the midships 0.4L. 3 The design stress for steel deckhouse plates may be taken as 0.90σy.

Figure 5-12. ABS Allowable Design Stress for Wheel Loaded Decks from ABS 3-2-3/Table 2

The calculation for nxx was shown above to be determined as:

nxx = ncgKv where Kv is determined from ABS 3-2-2/Figure 7 [1], which is shown above but is also repeated below in Figure 5-13 for ease of reference.

Figure 5-13. ABS Vertical Acceleration Distribution Factor KV, from ABS 3-2-2/Figure 7

This figure implies that the vertical acceleration from the stern to 0.5Lw forward of the stern will be less than the design vertical acceleration determined at the center of gravity of the vessel, ncg, i.e., it can be reduced to 80% of ncg from the stern to 0.4Lw. None of the calculations performed will utilize Kv < 1.0.

As shown in the equations for the plate thickness, the vertical acceleration, nxx, is required input to the analysis. To summarize from above, there are four different conditions to be investigated that result in the following ncg values:

Naval Craft, Operational ⇒ ncg = 0.24 g’s Naval Craft, Survival ⇒ ncg = 0.02 g’s Coastal Naval Craft, Operational ⇒ ncg = 0.17 g’s Coastal Naval Craft, Survival ⇒ ncg = 0.02 g’s

The simplest approach is to determine if there are any impacts when using the most severe conditions. Therefore, all loading and structural requirements for ABS will be initially investigated using the Naval Craft, Operational scenario with ncg = 0.24 g’s. Additional calculations will be developed below, as required, so that the full range of impacts can be assessed when investigating final locations on the Vehicle Deck for payload items that would overstress the existing deck structure if located at the worst location for nxx, i.e., at the bow of the vessel. If the finite element analyses developed later in this project confirm that all vehicle deck structure is acceptable using the maximum value for ncg then no additional analyses will be developed using the smaller values. It is recognized that this is an area for potential structural optimization that could be investigated for a new build project and it is recommended that designers recognize that all FEA is done with maximum design value for vertical acceleration, i.e., for vehicles located in the bow of the ship. It would be possible to develop lighter structure for other locations in the ship, other criteria not withstanding.

5.6.4 Boundary Conditions - Discussion on the ABS Plate Thickness Requirements & Loading Conditions in the Current Conversion

Before proceeding with specific deck plate requirements, it is important to present the following discussion regarding the boundary conditions assumed by the plate thickness requirements in the ABS equation and the loading conditions resulting from the tire footprints in the MEU loadout.

The boundary conditions assumed for the analysis of any plate panel have a direct impact on the requirements for the panel thickness. There are two extreme conditions that can generally be assumed to bracket most problems associated with the design of typical ship structure plating:

1. Fully Fixed. – These boundary conditions assume that all six degrees of freedom are resisted around all four boundaries of the plate panel. The six degrees of freedom are translation in the X, Y and Z directions and rotation about the same three axes. Under fully fixed conditions, a reaction will occur for each of these DOF’s. 2. Simply Supported. – These boundary conditions assume that five of the six degrees of freedom are restrained. The released DOF is the rotational restraint about the axis parallel to each edge of the plate. This implies that there is no resistance to bending, i.e., no bending moment at the boundary of the plate about the axis of primary concern.

The assumption of fully fixed boundary conditions will result in thinner, lighter plate than a plate experiencing the same load but with simply supported boundary conditions, which is why this consideration is important.

These two conditions are generally considered in the analysis of plate panels subjected to loads that are perpendicular, i.e., normal, to their surface, such as a tire load. When an individual plate panel is subjected to a load normal to its surface it is typically analyzed as simply supported. For the situation when adjacent panels are simultaneously subjected to normal loads then fixed conditions are often considered. Fixed boundary conditions may be assumed for a large area of stiffened panels subjected to hydrostatic loads, for instance. The loads imparted by tire footprints typically suggest analysis using simple support boundary conditions.

A comparison of the coefficients used by ABS and presented in Figure 5-11 to those presented in classical textbooks such as Roark, [6], confirms that the ABS equation assumes simply supported boundary conditions. This is perfectly acceptable and is consistent with sound engineering practice because most tire footprints are narrower than the deck stiffener spacing. However, this is not always true for the current conversion study and the assumption of simple supports may not be completely accurate which could result in greater, or lesser, plate thickness requirements than those resulting from the straight-forward application of the ABS equations.

The equation presented by Table 26, Case 1c in Roark [6] is for a simply supported plate panel with a centrally located rectangular patch load, similar to the tire footprint for the current condition. The equation in [6] is:

βW Maxσ = σ = b t 2

Where: σb = the maximum bending stress, located at the center of the panel W = central patch load t = plate thickness β = coefficient based on the plate and load footprint and aspect ratios

Roark provides a table of vales for β that is identical to the coefficients presented by ABS in their table, Figure 5-11. Simple manipulation of the Roark equation yields:

βW t = σ a

Where: σa = the allowable stress, replacing σb.

The only difference between this equation and that presented in the ABS rules is the factor for vertical acceleration. Obviously, the ABS equation reduces to the exact same form as that presented by Roark if the design acceleration, nxx = 0 so that both equations are using static 1g acceleration.

The reason that simple support boundary conditions are typically and accurately assumed for loading a single plate panel relates to the rotational restraint provided by the adjacent panel, i.e., it is assumed to be zero. Therefore, the boundary of the loaded panel will have a nonzero slope as shown below in Figure 5-14 (a), i.e., the slope of the deck plate at the stiffeners is non-zero. When two adjacent panels are equally loaded the rotation along the boundary between the two plates are offset by each other resulting in a zero slope at the boundary and effecting a fixed boundary condition.

A quick review of the tire footprints for the vehicles in Appendix C and Table 5-22, Table 5-23 and Table 5-24 shows that there are three different relationships between the tire widths of the loadout and the stiffener spacing on the vehicle deck:

1. Width of tire less than stiffener spacing, Figure 5-14 (a), – this is the typical scenario and will allow for the straight forward application of the equations presented by ABS. 2. Width of tire nominally greater than the stiffener spacing, Figure 5-14 (b), – deck thickness requirements may be reduced compared to those predicted from the ABS equations because portion of tire footprint that overlaps into adjacent panel will resist rotation of plate panel along the longitudinal stiffener and shift the response of the deck structure. This potential reduction will also have to be investigated for these same footprints when they are centered on the stiffener instead of the plate panel. This may be the governing condition that eliminates the possibility for plate reduction below the ABS formulation requirements. 3. Width of tire footprint significantly greater than stiffener spacing, Figure 5-14 (c), – Some tire footprints are approximately twice the stiffener spacing and can result in two adjacent plate panels simultaneously loaded. The reaction in the plating along the stiffener that separates these two panels will be significantly higher than predicted by the ABS equations assuming simple support.

Therefore, the end rotations resulting in the plate panels of Figure 5-14 (b) & (c) will differ from those assumed by the ABS equations, which will cause a different structural response than assumed by the ABS equations. The change in structural response results in a different set of moment distributions acting through the plate panels. This will be demonstrated by a few textbook examples illustrated below, see Figure 5-15 and Figure 5-16. Complete investigation of the various relationships between tire footprint, stiffener spacing and the resulting impact to the deck plating are investigated later in this project.

Typical tire footprint (a) that fits between stiffeners

Tire footprint for LAV = 279 mm (b) Symmetric about plate panel

210 mm

16” (406 mm) tire footprint of the (c) MK-48 LVS, Front Power Unit

Figure 5-14. Relationship of Tire Footprint Width to Stiffener Spacing

5.6.5 Continuous Span Beams with Various Load Scenarios

Detailed analysis will have to be conducted for the situations that arise from circumstances similar to Figure 5-14 (b). This type of overlap, it may not be symmetric as shown in the figure

above, is not covered as a typical situation in any textbook and direct analysis will be conducted later in this project. The results of these analyses are included in this report.

However, the loading conditions in Figure 5-14 (a) & (c) can be approximated as shown below in Figure 5-15 and Figure 5-16, respectively.

For a continuous span beam with only one span loaded, Figure 5-15 presents the resulting load, shear and moment diagrams:

LOAD

1 1 1

0.5wl 0.05wl

SHEAR

0.05wl 0.5wl

0.075wl2

MOMENT

0.05wl2 0.05wl2

Figure 5-15. Load, Shear & Moment Diagrams for Continuous Span Beam – One Span Loaded

For a continuous span beam with two spans loaded, Figure 5-16 presents the resulting load, shear and moment diagrams:

LOAD

1 1 1

0.383wl 0.583wl 0.033wl SHEAR

0.617wl 0.417wl

0.1167wl2 MOMENT

0.0735wl2 0.0534wl2

Figure 5-16. Load, Shear & Moment Diagrams for Continuous Span Beam – Two Adjacent Spans Loaded

Figure 5-15 illustrates the moment diagram resulting when there is only a single span loaded in a continuous span beam. Most tire footprints would not load the entire span, only a portion. Regardless, the same basic diagrams would result for a centrally loaded span, i.e., the maximum moment is at the center of the plate panel. The maximum moment in Figure 5-15 is equal to 0.075 wl2. The moment will be less than this maximum value if only a portion of the span is loaded. Figure 5-16, on the other hand, shows that the maximum value for two adjacent spans uniformly loaded is equal to 0.1167 wl2, which is greater than the value of 0.075wl2. The location of the maximum moment has also shifted from the center of the plate to the support, i.e., the stiffener. This is a clear demonstration that the assumption of simple support boundary conditions (assumed in the ABS equations) will not be sufficient for tire footprints that are twice the value of the stiffener spacing. It also suggests that there will be some intermediate value of tire footprint that is greater than the stiffener spacing but less than twice the spacing that might benefit the moment distribution in the plate panel by reducing the moment at the center of the

plate but has not yet caused the moment at the supports to be the governing value. This will be further investigated later in this project.

5.6.6 ABS Aluminum Extrusion Properties for 6061-T6

As stated above, the Main Vehicle Deck is fabricated using extrusions that are 6082-T6 (or 6061- T6). ABS does not provide properties for any 6082 aluminum alloys but does provide data in Table 3.3.2 for 6061-T6 as follows:

2 2 6061-T6 Ultimate Tensile Strength = Ual = 16.9 kg/mm = 165.5 N/mm = 24,000 psi 2 2 Welded Yield Strength = Yal = 14.13 kg/mm = 137.9 N/mm = 20,000 psi

These strengths are for the welded alloy using 5183, 5356 or 5556 filler wires and can be used in the ABS equations provided above. In the unwelded condition, 6061-T6 has a minimum yield strength of 24.6 kg/mm2 = 241.3 N/mm2 = 35,000 psi. ABS Table 3.3.2 also presents welded material properties using other filler wires, which are lower than those shown above. ABS suggests that the superior filler wires and corresponding properties shown above are the most commonly used.

5.6.7 Loads in Way of the Light Armored Vehicles (LAV) & Required Deck Plate

The military vehicle payload for the converted vessel specifies eight total LAV’s with weights ranging from 23,300 pounds to 28,400 pounds. As shown in Table 5-22 this does not represent the worst pressure load resulting from the tire loads however, with eight LAV’s in the loadout this is a good vehicle to investigate as it represents a significant portion of the loadout. As such, this represents a good baseline vehicle for determination of the tire footprint loads and the resulting structural requirements. It also represents the intermediate tire width depicted in Figure 5-14 (b) and allows for discussion on the preliminary design approach for the deck plate in way of these vehicles.

Four of the LAV’s are pictured below in Figure 5-18. They all have the same basic configuration including eight tires distributed over four axles. It has been assumed that their tires have individual footprints approximated by the Medium Cargo Truck Load as shown in Appendix C, Figure C-2. Assuming that the tires are loaded in the same ratio to the total vehicle weight as shown in Appendix C, it is approximated that the maximum tire load associated with the 28,400 pound LAV (R) is 3770 pounds, 16,770 N. It is also assumed that the tires have footprints that are similar to those of the Medium Cargo Truck, i.e., 22” x 11” or 559 mm x 279 mm.

In all likelihood, the LAV’s will have a predominantly longitudinal orientation on the PacifiCat and never have a transverse orientation. Even if they do have a transverse orientation the tire footprint is 559 mm, which means that the 3770 pound tire load would be distributed over more than two plate panels, i.e., the tire load on the plate panel would be a lot smaller than the longitudinal orientation. Therefore, this situation can be ignored for deck plating requirements.

A schematic of the Heavy Extrusion plate panel with the tire located at its center is shown below in Figure 5-17. Note – it is not possible for the complete tire load to be on one plate panel. This

is accounted for in the 2nd calculation shown below which uses a tire load equal to (210/279) x 3770 pounds = 2838 pounds.

For this arrangement: 320.5 mm (12.62 in) a/s = 210/210 = 1.0

b/s = 559/210 = 2.66 279 mm 559 mm (10.98) (22.0 in) 1200 mm l/s = 1200/210 = 5.7 (47.24 in)

From ABS: β = 0.30 210 mm (8.27 in)

Figure 5-17. Schematic Diagram of LAV Wheel Load on Heavy Extrusion

For:

β = 0.30, W = 3770 pounds, nxx = 0.24 x 2 (at the bow) and σa = 20,000 x 0.6 = 12000 psi

and using the equation provided above for the English units, the required ABS plate thickness becomes:

0.3()3770 (1 + 0.5(0.48)) t = = 0.342 in = 8.68 mm 12000

This is slightly less than the 9.80 mm plate thickness available in the heavier extrusion. However, if it is considered that the actual load on the plate panel is only (210/279) x 3770 = 2838 pounds then the required plate thickness becomes:

0.3()2838 (1 + 0.5(0.48)) t = = 0.297 in = 7.54 mm 12000

Also, recalling from the discussion presented above, the tire load on the adjacent panels may reduce the stress in the centrally loaded panels by helping to restrain rotation about that boundary of the plate. This would further reduce the required plate thickness determined above, effectively adding to the margin already seen in the last calculation.

Additional calculations will be performed for the LAV’s to investigate the deck plate requirements when the tire is centered on the stiffener instead of the plate panel. These calculations and results are developed later in this project and presented in the final report.

These calculations demonstrate that the LAV’s (Figure 5-18) could be parked at any location of the heavier extrusion. The last calculation also indicates that the LAV’s could be parked on the lighter extrusion.

LAV Logistics (L) LAV Command & Control (C2)

LAV Anti-Tank (AT) LAV Recovery (R)

Figure 5-18. Various Configurations of the Light Armored Vehicle, LAV

5.6.8 Other Vehicle Deck Plate Requirements IAW ABS HSNC Rule

Brief calculations shall be presented for some of the other critical vehicles included in the loadout.

5.6.8.1 Armored Combat Excavator

This is a tracked vehicle with a footprint similar to that shown in Appendix C, Figure C-5. The total track area is 2 x (25” x 180”) = 9000 in2. With a vehicle weight of 36,000 pounds the average deck pressure = 36,000/9000 = 4 psi. Since this will certainly load numerous deck plate panels simultaneously, it can be assumed that the panel experiences a uniform load of 4 psi over

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its entire surface. The plate panel area is (210 mm x 1200 mm)/(25.42) = 391 in2 resulting in a load W = 391 x 4 = 1564 pounds. Plugging this into the ABS equation with β = 0.5 results in a required plate thickness of t = 0.328 in = 8.4 mm. This is a very conservative estimate of the required plate thickness, which could be more accurately determined using the equations for a uniformly loaded plate over its entire surface. Regardless, the deck plate in way of the Heavy Extrusion is acceptable and, in all likelihood, so is the deck plate of the Light Extrusion.

5.6.8.2 MK-48 LVS, Front Power Unit

The tire loads resulting from this unit impart the largest pressure load on the deck, 15.8 psi over an area of 16 in x 27 in as presented in Table 5-22. The maximum tire load is 6830 pounds assumed to be uniformly distributed over the 16 in x 27 in (406.4 mm x 686 mm) footprint. Based on the 210mm (8.25 in) plate panel, the load on the panel is (8.27/16) x 6830 = 3530 pounds, which is equal to the load W in the ABS equation. With a/s = 210/210 = 1 and b/s = 686/1200 = 0.57 and l/s = 1200/210 = 5.7 implies that β = 0.57. Using these values results in an ABS required plate panel thickness of:

0.57()3530 (1+ 0.5(0.48) ) t = = 0.456in = 11.58 mm 12000

This thickness assumes that the boundary conditions for the plate panel are simply supported. As demonstrated by the loading and moment diagram information in Figure 5-16, this is not the case. As shown in the ABS equation for plate thickness, it can be demonstrated that the required thickness will vary as the square root of the moment, i.e., if the load W is doubled, the moment acting on the plate panel will double but the required plate thickness will only increase as (2 x W)1/2 = 1.414W. This is further reinforced recognizing that the section modulus for a unit width plate strip is calculated as:

2 SMplate = t /6

Where t is the thickness of the plate panel. This confirms that the ability of a plate panel to resist an increasing moment varies as the square of its thickness. Using this information, and the calculated required plate thickness of 0.456 inches, it can be calculated that the actual required deck plate thickness in way of the tire footprint on the MK-48 LVS will be:

[(0.1167wl2)/(0.075wl2)]1/2 x 0.456 = 0.568 in = 14.4 mm

This represents a significant increase to the existing deck plate, which is only 9.8 mm or 8.0 mm, depending on the location of the vehicle deck. (Actual requirement in way of 8.0 mm deck plate would be recalculated to account for the closer stiffener spacing.) Various options will be investigated to minimize this impact in way of this severe tire load. These will include:

• The use of locally thickened deck plate to accommodate these vehicles. Other vehicles having similar, severe requirements will be determined and accommodated in a localized area to minimize the amount of structural modifications.

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• Re-locate the vehicles so that they are closer to the center of gravity of the ship and will not experience the maximum value of design vertical acceleration, nxx, as assumed for these calculations. • Investigate the use of relaxed allowable stresses, which are currently based on the typical ABS design values for the design of a new vessel. Argument can be made that, for military application, there would be little damage allowing the plate to go to yield and perhaps experience slight permanent deformation. • Finite element analysis to more accurately predict the structural response of the vehicle deck structure.

The weight penalties associated with the various options will be investigated along with approximate cost and payload impacts.

5.6.8.3 Trailer, Cargo 3/4 T (M101A1)

This is one of the few vehicles for which the entire footprint can be contained on a single plate panel. The plate requirements for this wheel load will be checked for both of the extrusions. The footprint is 7 in x 12 in (178 mm x 305 mm).

• Heavy Extrusion a/s = 178/210 = 0.85 b/s = 305/210 = 1.45 l/s = 1200/210 = 5.7 ⇒ β = 0.46 W = 925 pounds nxx = 2 x 0.24 = 0.48 σa =20,000 psi

0.46()925 ()1 + 0.5(0.48) t = = 0.210in = 5.33 mm 12000

• Light Extrusion a/s = 178/200 = 0.89 b/s = 305/200 = 1.53 l/s = 1200/200 = 6.0 ⇒ β = 0.44 W = 925 pounds nxx = 2 x 0.24 = 0.48 σa =20,000 psi

0.44()925 ()1 + 0.5(0.48) t = = 0.205in = 5.21 mm 12000

In all cases, the deck plate structure in way of the Trailer, Cargo 3/4 T (M101A1) tire load is acceptable.

5.6.9 Vehicle Deck Longitudinal IAW ABS

The Vehicle Deck longitudinal stiffeners are designed in accordance with ABS HSNC Rules 3-2- 4 [1]. In accordance with Table 1 from this section of the ABS Rules the allowable design stress for aluminum deck longitudinal stiffeners that form a portion of an effective strength deck is:

σa = 0.33σy = 0.33 x 20,000 = 6600 psi

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This is a relatively small value for allowable stresses in deck longitudinals, which although they form a portion of a strength deck, may not be a portion of the uppermost strength deck and therefore may not be subjected to the extreme fiber stresses of the uppermost strength deck.

The ABS rules do not specify any calculation procedures, requiring only that all possible loading combinations be investigated for vehicle deck longitudinals. This implies that ABS is accepting a first principles approach to the determination of the shear and bending moment acting in the deck longitudinals. Therefore, a simplified analysis using a single span beam with a load along its length will be used to generate the shear and moment acting in the longitudinals. The load acting along the length of the beam represents the tire footprint acting on the deck.

Regardless, for this phase of the project the shear and moment acting in the longitudinal stiffeners of the Vehicle Deck will be calculated from the scenario shown in Figure 5-19.

a b c Longitudinal Tire footprint load stiffener along longitudinal wb

1200 mm L Transverse Transverse Frame Frame

Figure 5-19. Deck Longitudinal Loading Diagram for ABS Calculations

The maximum moment occurs at the midspan of the beam when a = c and is calculated as [7]:

wb ⎛ b ⎞ M max = ⎜a + ⎟ 2 ⎝ 4 ⎠

The maximum reaction/shear force will occur when either “a” or “c” is equal to zero and can be calculated as [7]: (Assuming a = 0)

wb V = ()2c + b max 2L

These values for Mmax and Vmax are both conservative because they are based on a single span beam, not the continuous span arrangement that actually exists on the vehicle deck. This estimate is provided for now in order to assess the fundamental requirements for the ABS deck longitudinals and establish the order of magnitude of the strength requirements for these elements. More refined analysis will be performed as the project continues. The results of these analyses are included in the final report.

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An important consideration is to determine the number of longitudinal stiffeners that will resist a given tire load. For instance, the tire footprint on the MK-48 LVS Front Power Unit have a 16 inch width which, in accordance with Figure 5-16, will never engage less than three longitudinal stiffeners.

Table 5-25 presents the shear force and bending moment to be resisted by the deck longitudinals by various tire footprints. The table also includes the number of deck longitudinals that are assumed to be engaged in resisting these forces.

The shear and moment values presented in Table 5-25 use the single span beam configuration shown in Figure 5-19. As discussed above, this produces conservative results compared to the continuous span beams that can actually be assumed for these analyses. As a comparison, a single span beam uniformly loaded along its entire span will develop a maximum moment of wl2/8 = 0.125 wl2. From above, Figure 5-15, it can be seen that a continuous span beam with a single span uniformly loaded will develop a maximum moment of 0.075wl2. Thus, the continuous span beam develops a maximum moment that is only 60% of the maximum moment in a single span beam subjected to the same load. It is expected that similar reductions will result upon detailed analysis, i.e., finite element analysis, of the current loading scenarios.

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Table 5-25. Vehicle Deck Longitudinal Stiffener Shear & Moment Loads – ABS Design – English Units

Vehicle Tire Footprint Load, w Total Shear, Total Moment, Number of Shear/long’l Moment/long’l Req’d Section Load on long’l (lb/in) V M deck long’s (lb) (in-lb) Modulus (lbs) (in) (lb) (in-lb) (in3) MK-48 LVS 6830 27 253 4879 57,606 3 1627 19,202 2.9 Front Power Unit Truck 7-T, 6100 25 244 4486 52,966 2 2243 26,483 4.1 MTVR Truck Tow 2000 14 143 1705 20,135 1 1705 20,135 3.1 Carrier, HMMWV Truck, Light 1200 9 134 1091 12,883 1 1091 12,883 2.0 Strike Vehicle (LSV) LAV Logistics 3743 22 171 2886 34,074 1* 2886 34,074 5.2 (L) Note: * The 11 inch breadth of this footprint, if centered on a specific deck longitudinal, will overlap into the effective breadth of deck plate of the two adjacent longitudinals, engaging each of them in the reaction to resist the imposed loads. Specifying 1 deck longitudinal in this table is very likely conservative. Detailed analysis of this loading arrangement will be investigated as the project continues.

ALL OF THE LOAD, SHEAR AND MOMENT VALUES IN THIS TABLE REFLECT A STATIC 1G LOAD.

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The available section modulus of the longitudinal stiffeners in the Heavy Extrusion has been estimated as 4.9 in3 (80.3 cm3). With an allowable stress of 6600 psi this suggests that the maximum moment that can be tolerated by the longitudinal stiffeners on the Heavy Extrusion is:

Maximum Allowable Moment, Heavy Extrusion = 4.9 x 6600 = 32,340 in-lb.

As shown in Table 5-25, the moment resulting from the LAV Logistics vehicles exceeds the capacity of the existing deck stiffening. Final decision regarding the capacity of the deck stiffening will be deferred until more detailed analysis can be performed that will include the beneficial effects of the continuous span as well as the penalizing effects of the design vertical acceleration.

The maximum allowable shear strength will be taken as 60% of the allowable bending stress:

σv all = 0.6 x 6600 = 3960 psi

The available shear area in stiffening of the Heavy Extrusions is 1.31 in2 resulting in a maximum allowable shear force of:

Maximum Allowable Shear, Heavy Extrusion = 1.31 x 3960 = 5188 lb.

From Table 5-25 above, it is seen that the maximum shear force is 2886 pounds and therefore the existing deck longitudinal stiffeners can satisfactorily resist all shear forces.

In general, it looks like the deck stiffening will be strong enough to accommodate the wheel loads resulting from the military vehicle payload specified for this conversion study.

5.6.10 Vehicle Deck Structure – DNV HSLC and Naval Vessel Rules

The following calculations will determine the Vehicle Deck plate and stiffening requirements using the same vehicles with DNV criteria as just used for the ABS calculations.

5.6.10.1 Vehicle Deck Plating – DNV Criteria

The DNV criteria for the design of deck structure subjected to vehicle wheel loads are contained in DNV Part 5, Chapter 2, Section 3 [2] of their rules. The design pressure to be taken over the area of the footprint is calculated as:

Q 2 p = ()9.81+ 0.5av (kN/m ) no ab

Where: Q = maximum axle load, metric tones n0 = number of tires on the axle a = tire footprint dimension parallel to stiffeners, meters b = tire footprint dimension perpendicular to stiffeners, meters 2 av = design vertical acceleration for the craft, m/s

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For the consideration of this design the value of av will be limited to the design values determined above and repeated below. For general DNV design practice it would be necessary to also check values of av = 6/√Q for moving cargo handling apparatus in port. This is not a consideration for the current conversion project since no cargo handling operations are assumed for this project.

2 acg = 23.5 m/s for Naval Surface Craft, Unrestricted notation

Once the design pressure, p, is determined it is used in the equation to determine the required plate thickness from DNV 5-2-3/A501 [2] which refers to the same formula used for steel deck plating in A201 with different definitions for the bending/stress parameter, mσ, which is all defined below:

77.4ka kwcsp t = + tk (mm) mσ

Where: ka = 1.1 – 0.25s/l maximum 1.0 for s/l = 0.4 minimum 0.85 for s/l = 0.1

4.2 a = tire footprint dimension kw = 1.3 − 2 , maximum 1.0 for a ≥ 1.94s, ⎛ a ⎞ parallel to the deck stiffening ⎜ +1.8⎟ ⎝ s ⎠

c = b for b < s = s for b > s

s = stiffener spacing

38 m = 2 for b/s ≤ 1.0 ⎛ b ⎞ b ⎜ ⎟ − 4.7 + 6.5 ⎝ s ⎠ s

m = 13.57 for b/s > 1.0

From DNV 5-2-3/A501 [2], the value of σ is to be determined as:

σ = σ0 f1

2 Where: σ0 = 180 N/mm (maximum) in general for seagoing conditions = 210 N/mm2 (maximum) in general for harbor conditions f1 = as given in DNV 3-3-1/A200 [2] with respect to plate material yield stress given in 3-3-2/Table B1, B2, B3 and B4

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2 For these applications for deck plate: σ0 = 180 N/mm f1 = 0.48 (welded condition Table B4) ⇒ σ = 86.4 N/mm2

For the most direct comparison to ABS, the calculations for the Trailer, Cargo 3/4 T (M101A1) will be performed for both the Heavy and Light Extrusion. This was the only tire footprint that fit within the stiffener spacing and is therefore felt to yield the most accurate comparison using the ABS and DNV equations because it satisfies the assumed boundary conditions, as discussed above.

5.6.10.2 Trailer, Cargo 3/4 T (M101A1)

This is one of the few vehicles for which the entire footprint can be contained on a single plate panel. The plate requirements for this wheel load are checked for both of the extrusions. The footprint is 7 in x 12 in (178 mm x 305 mm).

Q = 1850 pounds = 1850/2204 = 0.84 metric tonnes (1850 lbs from Table 5-22) n0 = 2 2 acg = 23.5 m/s

• Heavy Extrusion a = 0.305 meters b = 0.178 meters s = 0.210 meters l = 1.2 meters

0.84 p = ()9.81+ 0.5()23.5 = 166.8 kN/m2 2()()0.305 0.178

To determine the required deck plate, the corresponding variables are calculated as: ka = 1.1 – 0.25(.210)/(1.200) = 1.06 use max of 1.0

4.2 kw = 1.3 − 2 = 0.903 ⎛ 0.305 ⎞ ⎜ +1.8⎟ ⎝ 0.210 ⎠ c = 0.178 meters s = 0.210 meters p = 166.8 kN/m2 b/s = 0.8476 ⇒ m = 11.75

From which the required deck plate becomes:

77.4()(1.0 0.903 )()0.178 (0.210)(166.8) t = + tk = (5.76 + tk) mm 11.75x86.4

• Light Extrusion a = 0.305 meters b = 0.178 meters s = 0.200 meters l = 1.2 meters

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0.84 p = ()9.81+ 0.5()23.5 = 166.8 kN/m2 2()()0.305 0.178

To determine the required deck plate, the corresponding variables are calculated as: ka = 1.1 – 0.25(.200)/(1.200) = 1.04 use max of 1.0

4.2 kw = 1.3 − 2 = 0.920 ⎛ 0.305 ⎞ ⎜ +1.8⎟ ⎝ 0.200 ⎠ c = 0.178 meters s = 0.200 meters p = 166.8 kN/m2 b/s = 0.89 ⇒ m = 12.22

From which the required deck plate becomes:

77.4()(1.0 0.920 )(0.178)(0.200)(166.8) t = + tk = (5.57 + tk) mm 12.22x86.4

The only reference for tk was found for pneumatic tires in DNV 5-2-3/A202 [2], where it is defined as a corrosion addition with a value of tk = 0 mm. Therefore, nothing will be added to the deck plate values calculated above. Discussion with DNV confirms that this variable is left over from steel vessel application and need not be considered for aluminum HSC.

From above, it is seen that this is close to, but slightly heavier than the deck plate calculated by the ABS equation, which determined a required deck plate of 5.33 mm for the Heavy Extrusion and 5.21 mm for the Light Extrusion. Both societies use similar allowable stresses based on the welded condition of the material. The ABS design uses an allowable stress of 12,000 psi whereas the DNV design uses the value of 12,530 psi (0.48 x 180 N/mm2). In practical application, both rule set calculations would result in the use of 6 mm plate for this vehicle although some builders might select 5.5 mm plate if designing to the ABS criteria.

5.6.10.3 Vehicle Deck Plate – Light Armored Vehicle

The coefficient “m’ used in the DNV plate formulation includes an option for width of tire greater than the stiffener spacing, i.e., b/s > 1 ⇒ m = 13.57, as shown above. The following information is also used to generate the required vehicle deck plate in way of the LAV using the DNV criteria.

Q p = ()9.81+ 0.5av no ab

Q = 3770 x 2/2204 = 3.421 m tonnes (3770 lbs from Table 5-22) 2 n0 = 2 a = 0.559 meters (22”) b = 0.279 meters (11”) av = 23.5 m/s

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3.421 p = ()9.81 + 0.5()23.5 = 236.5 kN/m2 2()()0.559 0.279

To determine the required deck plate, the corresponding variables are calculated as: ka = 1.1 – 0.25(.210)/(1.200) = 1.06 use max of 1.0

4.2 kw = 1.3 − 2 = 1.09 ⇒ use maximum value of 1.0 for a ≥ 1.94s ⎛ 0.559 ⎞ ⎜ +1.8⎟ ⎝ 0.210 ⎠ c = 0.210 meters s = 0.210 meters p = 236.5 kN/m2 b/s = 1.33 ⇒ m = 13.57

From which the required deck plate becomes:

77.4()()()1.0 1.0 0.210 (0.210)(236.5) t = + t k = (7.30 + tk) mm 13.57x86.4

The deck plate required using the ABS criteria is 7.54 mm, again almost identical to that required using DNV.

5.6.10.4 Vehicle Deck Plate - MK-48 LVS, Front Power Unit

This represents the extreme case analyzed above using a combination of the ABS design equations and other factors to estimate the Vehicle Deck plate thickness in way of this vehicle. The following calculations present the Vehicle Deck plate required in way of this vehicle using DNV criteria.

Q p = ()9.81+ 0.5av no ab

Q = 6830 x 2/2204 = 6.198 m tones (6830 lbs from Table 5-22) 2 n0 = 2 a = 0.686 meters (27”) b = 0.406 meters (16”) av = 23.5 m/s

6.198 p = ()9.81+ 0.5()23.5 = 239.9 kN/m2 2()()0.686 0.406

To determine the required deck plate, the corresponding variables are calculated as: ka = 1.1 – 0.25(.210)/(1.200) = 1.06 use max of 1.0

4.2 kw = 1.3 − 2 = 1.14 ⇒ use maximum value of 1.0 for a ≥ 1.94s ⎛ 0.686 ⎞ ⎜ +1.8⎟ ⎝ 0.210 ⎠

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c = 0.210 meters s = 0.210 meters p = 239.9 kN/m2 b/s = 1.93 ⇒ m = 13.57

From which the required deck plate becomes:

77.4()()1.0 1.0 (0.210)(0.210)(239.9) t = + tk = (7.35 + tk) mm 13.57x86.4

This is significantly lighter than the deck plate determined using the modified ABS approach, 11.57mm. Additional work will be done to investigate the required deck plate in way of this vehicle. This will include the development of simple finite element models to assess the deck requirements when subjected to this wheel load.

It will be assumed for now that similar results will happen using the DNV analysis for the other wheel loads, i.e., the DNV equations will result in smaller deck thickness requirements than those from ABS. More detailed development of these calculations are preformed later in this project with the results included in the final report.

Noting that the plate thickness required from the DNV formulations is less severe than that resulting from ABS can be attributed to various factors, perhaps the most obvious being the allowable stress used in the two different rules. Regardless, this result also confirms that the DNV equations are based primarily on the assumption of simple support boundary conditions for the plate, except for the consideration of the coefficient, “m”.

Table 5-26 presents a summary of the ABS and DNV Vehicle Deck plate thicknesses calculated in this report.

Table 5-26. Comparison of ABS & DNV Vehicle Deck Plate Requirements

Vehicle ABS Req’d Plate DNV Req’d Plate (mm) (mm) Light Armored 7.54 7.27 Vehicle, LAV* MK-48 LVS, Front 11.57 7.35 Power Unit* Trailer, Cargo 3/4 T (M101A1) 5.33 5.76 Heavy Extrusion Trailer, Cargo 3/4 T (M101A1) 5.21 5.57 Light Extrusion Note * These vehicles have tire footprints where the smaller footprint dimension exceeds the stiffener spacing. Detailed calculations will be performed to more accurately determine the Vehicle Deck plate requirements. ABS does not include any contingency in their design algorithms for such a tire footprint.

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5.6.11 Vehicle Deck Stiffening – DNV Criteria

The criteria for aluminum deck stiffening is presented in DNV 5-2-3/A600 [2], which refers to 5- 2-3/A300 for use of the same equations as presented for steel, substituting different allowable stress in the form of σ = σ0 f1. The equation to be used for section A300 is given as:

1000k lcdp Z = z + Z mσ k for use in this application:

2 2 σ0 = 160 N/mm f1 = 0.48 ⇒ σ = 76.8 N/mm (11,140 psi compared to 6600 psi for ABS) kz = 1.0 for b/s < 0.6 and b/s > 3.4

⎛ b ⎞ k z = ⎜1.15 − 0.25 ⎟ for 0.6 < b/s < 1.0 ⎝ s ⎠

⎛ b ⎞ b k z = ⎜1.15 − 0.25 ⎟ for 1.0 < b/s < 3.4 ⎝ s ⎠ s c = b for b < s = s for b > s d = a for a < l = l for a > l a, b and p as given above

r m = 2 for a/l ≤ 1.0 ⎛ a ⎞ a ⎜ ⎟ − 4.7 + 6.5 ⎝ l ⎠ l

87 m = for 1.2 < a/l ≤ 2.5 2 2 ⎛ a ⎞ ⎡⎛ a ⎞ a ⎤ ⎜ ⎟ ⎢⎜ ⎟ − 6.3 +10.9⎥ ⎝ l ⎠ ⎣⎢⎝ l ⎠ l ⎦⎥ m = 12 for a/l ≥ 3.5 r = factor depending on the rigidity of the girders supporting the continuous stiffeners, taken as 29 unless better support conditions are demonstrated. = 38 when continuous stiffener may be considered as rigidly supported at each girder. r shall be taken as 29 for these calculations.

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No definition for Zk was available in the DNV rules [2].

Table 5-27 provides a summary of the relevant input data and load calculation, p, for the design pressure acting on the vehicle deck to be used as input for the required section modulus calculation, Z.

Table 5-28 is provided below to show the DNV section modulus requirements for the same vehicles that were used for ABS and presented in Table 5-25. In order to provide a simple comparison the value of av, design vertical acceleration, was taken equal to zero so that both the ABS and DNV stiffener requirements are currently based on static 1g loads. Similar to ABS, av will be included as the design progresses.

Table 5-27. Vehicle Data & Load Calculation for DNV Stiffeners

Vehicle Axle Load, Q “a” “b” No of tires, Design Pressure, p 2 (tonnes) (m) (m) no (kN/m ) MK-48 LVS Front 6.202 0.686 0.406 2 109.2 Power Unit Truck 7-T, MTVR 5.539 0.635 0.406 2 105.4 Truck Tow Carrier, 1.816 0.356 0.318 2 78.7 HMMWV Truck, Light Strike 1.090 0.229 0.229 2 102.0 Vehicle (LSV) LAV Logistics (L) 3.399 0.559 0.279 2 106.9

For the balance of the DNV stiffener and required section modulus calculations: s = 0.210 meters l = 1.200 meters σ = 76.8 N/mm2

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Table 5-28. Vehicle Deck Longitudinal Stiffener Section Modulus Requirements – DNV Design – METRIC UNITS

Vehicle “a” “b” “b/s” kz “c” “d” “a/l” m Z (m) (m) (cm3) MK-48 LVS Front 0.686 0.406 1.933 1.289 0.210 0.686 0.572 7.007 45.2 Power Unit Truck 7-T, MTVR 0.635 0.406 1.933 1.289 0.210 0.635 0.529 6.754 41.9 Truck Tow Carrier, 0.356 0.318 1.514 1.168 0.210 0.356 0.297 5.585 19.2 HMMWV Truck, Light Strike 0.229 0.229 1.090 0.956 0.210 0.229 0.191 5.143 13.2 Vehicle (LSV) LAV Logistics (L) 0.559 0.279 1.329 1.087 0.210 0.559 0.466 6.406 33.3

These calculations assume that the vehicles are parked on the deck oriented longitudinally as shown in the parking arrangement earlier in this report. This will place the long tire footprint dimension in the longitudinal direction, i.e., parallel to the deck stiffening and equal to dimension “a”, in accordance with the DNV definitions. The short dimension is ”b”, perpendicular to the stiffener.

ALL OF THE LOAD, SHEAR AND MOMENT VALUES IN THIS TABLE REFLECT A STATIC 1G LOAD.

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Table 5-29 and Table 5-30 present comparisons of the required section modulii for the Vehicle Deck stiffening using the ABS and DNV design criteria. Table 5-29 presents the comparison using the actual section modulus values calculated above, which were all based on static 1g loads. Table 5-30 modifies the required section modulii to account for the maximum values of design vertical acceleration, as would be required for the actual conversion. The values in Table 5-30 were increased by 1.48g’s to account for the ABS requirements and 3.4 g’s to account for the DNV requirements. The DNV required section modulii are still below those required by ABS. Further explanation for this is provided in Table 5-31, which shows the allowable stresses for the ABS and DNV design for both plate and stiffener considerations. As indicated in this table, the allowable stress for DNV stiffener design is approximately 225% greater than the ABS allowable stiffener stress. Since all of these allowable stresses are based on the welded yield strength of the aluminum, the reduced values used by ABS imply a greater factor of safety, perhaps accounting for material degradation due to welding.

Table 5-29. Comparison of ABS & DNV Vehicle Deck Section Modulus Requirements – Static 1g Loading

Vehicle ABS Req’d DNV Req’d SM SM (cm3) (cm3) MK-48 LVS Front 47.9 15.1 Power Unit * Truck 7-T, MTVR* 66.4 21.0 Truck Tow 50.4 19.2 Carrier, HMMWV Truck, Light Strike 32.0 13.2 Vehicle (LSV) LAV Logistics (L) 84.8 33.3 Note: * These values have been reduced from Table 5-28 to account for the number of deck longitudinal stiffeners that, as shown in Table 5-25, will resist the loads applied by these vehicles.

Table 5-30. Comparison of ABS & DNV Vehicle Deck Section Modulus Requirements with Respective Design Accelerations

Vehicle ABS Req’d DNV Req’d SM SM (cm3) (cm3) MK-48 LVS Front 140.0 51.3 Power Unit Truck 7-T, MTVR 193.9 71.4 Truck Tow 147.3 65.3 Carrier, HMMWV Truck, Light Strike 93.2 44.9 Vehicle (LSV) LAV Logistics (L) 247.8 113.2

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Table 5-31. Comparison of ABS & DNV Allowable Stresses for Plate & Stiffener Design

Classification Society Allowable Stress, Plate Allowable Stress, Stiffener N/mm2/(psi) N/mm2/(psi) ABS 62.1/(12000) 34.1/(6600) DNV 86.4/(12,530) 76.8/(11,140)

5.6.12 Vehicle Tie-Down Loads

It was originally expected that a typical calculation for the tie down requirements based on actual vehicle weight and ship motions would be required for this portion of the project. Reference [3], USMC Marine Lifting and Lashing Handbook, simplifies all of this. It presents tie down and lashing requirements based on vehicle weight and the type of ship used for transport. Large ships are shown to have lower requirements due to the reduced vessel motions in a seaway.

Therefore, all tie down and lashing requirements are developed using reference [3].

It was anticipated that the tie-down requirements would be similar for the two class societies and that accommodating the tie-downs would not be a big discriminator for one set of rules over the other. Using reference [3] will result in identical tie-down requirements for both conversions. Tie down arrangements and details are discussed later in the report and all tie down procurement and installation costs are included in the final cost estimate included with the report.

5.7 CONCLUSIONS TO STRUCTURAL LOADS REQUIRED FOR CONVERSION

As shown throughout the tables presented in Section 5 of this report, the ABS and DNV rules result in different hull girder and secondary slam loads to be resisted by ship structure. They also result in different Vehicle Deck requirements to satisfy the local strength criteria in this area. Many of the global and secondary slam loads predicted by DNV are larger than the corresponding loads determined through ABS. With different allowable stresses, it is not obvious which of these loading/allowable stress systems will result in the heavier hull girder and local structure required to resist the respective loads. These calculations are developed in the next section of this report to confirm the impacts from each of the class societies.

Additional calculations are also developed in the next section to finalize the impacts to the Vehicle Deck structure to accommodate this portion of the mission of the vessel.

The structural drawings of the PacifiCat are marked-up and presented in the next section of the report indicating the different structural schemes required by each of the societies. The weight estimates resulting from each of the structural modifications are also developed and presented in the next section of the report.

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6.0 STRUCTURAL MODIFICATIONS REQUIRED FOR CONVERSION

6.1 INTRODUCTION

This section presents the structural modifications that are required to resist the ABS and DNV loads developed in the previous section of this report. Hull girder and local structural properties were calculated and are presented below. No strength data was available from the original design so all strength properties were calculated for this project and may differ slightly from those used in the original design.

The strength data presented below is used with the global hull girder and secondary slam loads to determine the structural modifications required for the PacifiCat to operate in compliance with the unrestricted, open-ocean criteria for both ABS and DNV. Marked-up drawings are presented that show the structural modifications required for both the ABS and DNV conversions.

Structure on the Main Vehicle Deck is also evaluated for modifications required to accommodate the military vehicle payload for both ABS and DNV. A sketch is provided that shows the installation detail for the typical vehicle tiedown.

Finally, this section also provides estimates to the range, speed and endurance for the PacifiCat after the modifications have been incorporated. This is done using the weight estimates that have also been developed for the structural conversion requirements.

6.2 HULL GIRDER PROPERTIES & REQUIRED STRUCTURE

There was no clear definition of a strength deck provided on the drawings or within the notes that were available for this task. Engineering judgment determined that the uppermost strength deck of the PacifiCat is the TIER 3 Deck, directly above the Upper Vehicle Deck, approximately 14.1 meters above baseline. The TIER 3 Deck is shown as the uppermost deck on the midship section of the PacifiCat and all side shell plating and structure appears to be continuous up to this level on the shell expansion. The structure appears to be discontinuous above TIER 3, which is consistent with the knowledge that the upper passenger deck structure is not continuous with the hull girder. These observations suggest that the TIER 3 Deck is the uppermost strength deck of the ship. The only confirmation of the strength deck is the PacifiCat brochure information shown in Section 3.5.2 Structural/Superstructure of this report, which cites the T3 strength deck.

Various models of the PacifiCat structure were developed for use in the HECSALV software package, where the hull girder properties were calculated. Using the appropriate effective material, hull girder properties were calculated for both longitudinal and transverse bending. The ineffective material for openings and their shadow areas was not included in the section property calculations. Transverse bending is the action of prying apart or squeezing together of the two hulls under the action of global transverse loads. The hull girder properties are shown in Table 6-1 and Table 6-2. Figure 6-2 provides a schematic that identifies various areas of the hull from the Main Vehicle Deck to the Keel of the vessel.

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Table 6-1. PacifiCat Hull Girder Properties to Resist Vertical Bending at Midship

Property Value Value Cross Sectional Area 13,339.97 cm2 Moment of Inertia 236,743.70 cm2 m2 Section Modulus, Deck 34,685.58 cm2 m 3,468,558 cm3 Section Modulus, Keel 32,575.32 cm2 m 3,257,532 cm3 Shear Area 5409.67 cm2 NA, deck 6.83 m NA, keel 7.27 m

Table 6-2. PacifiCat Hull Girder Properties to Resist Transverse Bending

Property Value Value Cross Sectional Area 39,441.75 cm2 Moment of Inertia 350,509.90 cm2 m2 Section Modulus, TIER 3 60,685.73 cm2 m 6,068,573 cm3 Section Modulus, Wet Deck 125,276.80 cm2 m 12,527,680 cm3 Shear Area 10,255.48 cm2 NA, deck 5.78 m NA, keel 2.80 m

The information in Table 6-3 presents a summary of the global loads that the hull girder needs to resist for its original design as well as the ABS and DNV conversion designs.

Table 6-3. Summary of Global Loads Required for Original Design and Conversions

Max Transverse Torsional Slam Pitch Crest Hollow Vertical kN - m kN - m Induced Connecting Landing Landing Moment kN - m kN-m kN-m kN-m kN - m ABS Naval, 161,123 127,636 273,143 101,539 NA NA NA Operational ABS Naval, 161,123 104,991 224,682 83,524 NA NA NA Survival DNV 245,774 130,527 241,633 NA 533,093 120,939 169,564 Unrestricted Operational DNV 245,774 76,901 100,873 NA 222,547 118,316 165,031 Unrestricted Survival R4 – Original 165,031 76,900 100,873 NA 222,547 118,316 165,031 Design

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6.2.1 Hull Girder Stresses in the Original R4 Design

From Table 6-3 it is seen that the vertical bending moment for the original R4 design was calculated as 165,031 kN-m. Using the hull girder properties from Table 6-1 results in the following stresses:

• Stress at TIER 3 Deck = 165,031,000/3,468,558 = 47.58 N/mm2 • Stress at Keel = 165,031,000/3,257,532 = 50.66 N/mm2

In accordance with the DNV criteria (3.3.4/B101), the allowable primary stress, σ, is taken as 175 f1 where f1 is a material reduction factor determined from tables within DNV to help determine the actual allowable stress for a given alloy/temper in a given function, i.e., primary or secondary. The midship section drawing indicates that the TIER 3 Deck consists of both extruded and rolled structure. As scaled from the midship section, TIER 3 is fabricated from extrusions from ship centerline to 9.4 meters off center, P/S. The outboard 2.75 meters of TIER 3 is fabricated from rolled structure. Both the Upper Vehicle Deck and the Main Vehicle Deck are fabricated from extrusions. In accordance with Drawing No. 1811/2-201 Rev D all extrusions for this ship are either 6061 T6 or 6082 T6, each with a yield strength of 115 MPa. Review of hull bottom plating and Wet Deck structural drawings does not specifically define the material used for fabrication, however review of Dwg No 1811/2-201 Rev D suggests that all these structural components are fabricated from either 5083 H321 or H116, 5086 H32 or H116 or 5383 H321 or H116. The f1 factors for all of these materials are presented below in Table 6-4, which is excerpted from the DNV rules. The values for f1 shown in Table 6-4 reflect the material in its welded condition. DNV also presents values of f1 for all these materials in their unwelded conditions.

Table 6-4. Information Extracted from DNV 3.3.2/Table B4

DNV Material Temper Filler f1 Designation NV 5083 H116, H321 5356 0.531 H116, H321 5183 0.601 NV 5086 0, H111, H116, H32, 5356-5183 0.42 H34 NV 5383 H116, H34 5183 0.642 NV 6061 T4 5356-5183 0.48 T5/T6 0.48 NV 6082 T4 5356-5183 0.46 T5/T6 0.48

Notes: 1 The utilization of the material is higher than given by the f1 factor as given in Sec 1A. This is due to extended utilization in Rules for HS, LC and NSC, f1 = (σ1/240) x 1.10.

2 The utilization of the material is higher than given by the f1 factor as given in Sec 1A. This is due to extended utilization in Rules for HS, LC and NSC, f1 = (σ1/240) x 1.10.

Based on Table 6-4 it is easy to define f1 = 0.48 for the entire Upper Vehicle Deck, Main Vehicle Deck and the extruded portions of TIER 3. The appropriate values for other areas of the ship are

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not as easily defined. Regardless, it can be seen that only one material results in a value of f1 less than that used for the extrusions with all others being greater. As a conservative check it is assumed that the bottom shell plate and outboard strake of TIER 3 are fabricated from 5086 with 2 f1 = 0.42 resulting in an allowable stress of σ = 175 x 0.42 = 73.5 N/mm .

Based on the stresses calculated above, this would indicate that the hull girder properties and loads determined for the original R4 PacifiCat are consistent and result in an acceptable design.

Neither the original loads nor the original hull girder properties were available for this project. Similarly, it was not possible to uniquely define all the alloys in the different areas of the ship. Therefore, these calculations help to confirm the accuracy the work presented in this report.

The calculations demonstrated above can be rewritten to confirm compliance with DNV 3.3.4/B101 where:

M Z = x103 (cm3 ) σ

Where: Z = Required hull girder section modulus, cm3 M = Governing vertical bending moment, kNm 2 σ = allowable stress = 175 f1, N/mm

From this it is seen that:

Z = (165,031/84) x 1000 = 1,964,655 cm3

From Table 6-1 it is seen that the minimum section modulus is 3,257,532 cm3, satisfying the DNV criteria.

To determine the hull girder stresses when the original R4 design was subjected to transverse bending the loads from Table 6-3 and the hull girder properties from Table 6-2 are used:

• Stress at TIER 3 Deck = 76,900,000/6,068,573 = 12.67 N/mm2 • Stress at Wet Deck = 76,900,000/12,527,680 = 6.14 N/mm2

DNV 3-3-4/E100 defines typically acceptable stresses for transverse hull girder strength as 160f1. Table 6-4 shows the value for f1 for 6061/6082 as f1 = 0.48 resulting in an allowable normal stress of 76.8 N/mm2 for the TIER 3 Deck, well above the actual stresses predicted for transverse bending. For the Wet Deck, the minimum possible value is f1 = 0.42 resulting in an allowable stress of 67.2 N/mm2, also well above the actual stresses determined above.

6.2.2 ABS and DNV Buckling Criteria

An important consideration in any design, especially a conversion that contains a lot of relatively light plating, is the buckling capacity of the structure subjected to the new loads. Both ABS and DNV use the same “first principle’s” approach to this aspect of the design and, as such, they both contain the same equations and procedures to check for buckling. Although slightly redundant, both of those procedures are presented below. This is done for completeness within this report

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and also to provide definitions for the terms used by each society, which differ in each rule set, although the equations are all the same.

Only a portion of the buckling criteria from each rule set is reproduced in this report. Both rule sets include the calculation procedures for determining the buckling capacity for numerous situations that are not being checked in the current design, such as plate panels subjected to bi- axial compression and shear. The nature of this task allows for the determination of the principal buckling capacities. These include uni-axial compression of the strength deck plate subjected to longitudinal and transverse bending along with lateral stability of the stiffeners that support the deck. It is that information which is reproduced below.

This section of the report also includes calculations for the buckling capacity of the TIER 3 strength deck structural components, which consists of very light scantlings, deck plate that is 3.70 mm thick with 70 x 40 IT longitudinal stiffeners on 200 mm centers. Buckling of the lower flange of the vessel, i.e., the Wet Deck or Bottom Shell, will not be considered if TIER 3 is acceptable because, similar to most ships, the structure along these lower flanges is more robust than associated with the strength deck.

All calculations performed below assume uniform compression of the strength deck when subjected to transverse and longitudinal hull girder bending.

6.2.2.1 ABS Buckling Criteria

ABS presents their buckling criteria in two different areas of the rules. Plate buckling is covered within ABS HSNC 3-2-3/1.5 “Buckling Criteria” whereas stiffeners are covered in 3-2-4/1.5 “Elastic Buckling of Longitudinal Members.”

• ABS 3-2-3/1.5.1 Uni-Axial Compression

The ideal elastic stress is given as:

2 ⎛ tb ⎞ 2 σ E = 0.9m1 E⎜ ⎟ (N/mm ) ⎝ s ⎠

2 Where: σE = ideal elastic buckling stress, N/mm m1 = buckling coefficient as given in ABS 3-2-3/Table 3 E = modulus of elasticity = 69,000 N/mm2 for aluminum tb = thickness of plating, mm s = shorter side plate panel, mm l = longer side plate panel, mm

For the current design of PacifiCat and the TIER 3 strength deck:

For uni-axial compression on the short edge of plate (longitudinal bending):

2 tb = 3.70 mm; s = 200 mm; l = 1200 mm; m1 = 4.0 ⇒ σE = 85.01 N/mm

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For uni-axial compression on the long edge of plate (transverse bending):

2 2 2 2 ⎡ ⎛ s ⎞ ⎤ ⎡ ⎛ 200 ⎞ ⎤ m1 = C2 ⎢1 + ⎜ ⎟ ⎥ =1.21⎢1 + ⎜ ⎟ ⎥ =1.278 and ⎣⎢ ⎝ l ⎠ ⎦⎥ ⎣⎢ ⎝1200 ⎠ ⎦⎥ with C2 = 1.21 for angle and T profile stiffeners.

2 tb = 3.70 mm; s = 200 mm; l = 1200 mm; m1 = 1.278 ⇒ σE = 27.16 N/mm

The critical buckling stress, σc, is defined as:

σc = σE when σE ≤ 0.5σy

⎛ σ ⎞ σ = σ ⎜1 − y ⎟ when σ > 0.5σ c y ⎜ ⎟ E y ⎝ 4σ E ⎠

2 Where: σy = yield stress of material, N/mm . Generally the unwelded yield strength may be used but due account should be made for critical or extensive weld zones.

2 For TIER 3 extrusions fabricated from 6061 T6, the ABS value for σy welded = 137.9 N/mm 2 (20,000 psi) and the value for σy unwelded = 241.3 N/mm (35,000 psi). (See Table 6-5 for material properties.)

2 ⎛ 137.9 ⎞ For longitudinal bending: σE = 85.01 N/mm > σy welded/2 ⇒ σc = 137.9⎜1 − ⎟ = 82.0 ⎝ 4()85.01 ⎠ N/mm2 (worst case assumption, i.e., welded values for the strength of material).

2 2 For transverse bending: σE = 27.16 N/mm < σy welded/2 ⇒ σc = 27.16 N/mm (worst case assumption).

The buckling capacity of the longitudinal stiffeners subjected to axial compression is developed in ABS 3-2-4/1.5:

• ABS 3-2-4/1.5 Elastic Buckling of Longitudinal Members

EI a 2 σ E = 2 (N/mm ) C1 Al

4 Where: Ia = moment of inertia, including plate flange, cm 2 C1 = 1000 for N/mm A = cross-sectional area including the plate flange, cm2 l = stiffener span, m

The properties of the longitudinal stiffener on the TIER 3 strength deck are approximated from the 70 x 40 IT as:

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4 2 2 Ia = 99.9 cm A = 11.23 cm ⇒ σel = 426.3 N/mm ⇒ significantly greater than yield strength or allowable stress.

6.2.2.2 DNV Buckling Criteria

DNV 3-3-10 provides guidance on Buckling Control for both plate and stiffening.

The allowable, or critical compressive stress, σc, is a function of the ideal elastic, Euler, buckling stress, σel. These quantities are calculated below as reproduced from the appropriate sections of the DNV HSLC & NSC rules.

• DNV 3-3-10/A102 – Relationships

σ σ = σ when σ < f c el el 2

⎛ σ ⎞ σ σ = σ ⎜1 − f ⎟ when σ > f c f ⎜ ⎟ el ⎝ 4σ el ⎠ 2

2 Where: σc = critical compressive buckling stress, N/mm 2 σel = ideal elastic Euler compressive buckling stress, N/mm 2 σf = minimum upper yield stress of material, N/mm . Usually base material properties are used, but critical or extensive weld zones may have to be taken into account.

For the current design, the yield strength of the strength deck is taken from Dwg 1811/2-201D 2 which shows all extrusions having a yield strength of σf = 115 N/mm , which varies from the value used for ABS and is used below to provide a different set of allowable stress values.

• DNV 3-3-10/D100 – Plate Panel in uniaxial compression

2 ⎛ t ⎞ 2 σ el = 0.9kE⎜ ⎟ (N/mm ) ⎝1000s ⎠

Where: E = modulus of elasticity = 69,000 N/mm2 for aluminum t = plate thickness, mm s = shortest side of plate panel, m 8.4 k = k = for (0 ≤ Ψ ≥ 1) for plating with stiffener in direction of l Ψ +1.1 compression. 2 2 ⎡ ⎛ s ⎞ ⎤ 2.1 k = k s = c⎢1+ ⎜ ⎟ ⎥ for (0 ≤ Ψ ≥ 1) for plating with stiffener ⎣⎢ ⎝ l ⎠ ⎦⎥ Ψ +1.1 perpendicular to compression. c = 1.21 for angle or T stiffeners

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l = longest side of plate panel, m Ψ = ratio of smaller to larger compressive stress acting on the panel.

For these calculations of the TIER 3 strength deck capacity, the following values are used:

t = 3.70 mm s = 0.2 m l = 1.2 m Ψ = 1.0 c = 1.21

2 which results in: kl = 4.0 and σel longitudinal = 85.01 N/mm and 2 ks = 1.278 and σel transverse = 27.16 N/mm

With the information developed so far the following values are determined:

A. For longitudinal bending considerations of the TIER 3 strength deck:

2 2 σf = 115 N/mm , σel longitudinal = 85.01 N/mm ⇒ σel longitudinal > σf/2 therefore:

⎛ 115 ⎞ 2 σc longitudinal = 115⎜1 − ⎟ = 76.11 N/mm ⎝ 4()85.01 ⎠

B. For transverse bending considerations of the TIER 3 strength deck:

2 2 σf = 115 N/mm , σel transverse = 27.16 N/mm ⇒ σel transverse < σf/2 therefore:

2 σc transverse = 27.16 N/mm

• DNV 3-3-10/E100 – Lateral buckling mode (of longitudinal stiffeners)

E 2 σ el = 10 2 (N/mm ) ⎛ l ⎞ ⎜100 ⎟ ⎝ i ⎠

I Where: i = A A 4 IA = moment of inertia of stiffener, cm A = cross sectional area of stiffener, cm2

The longitudinal stiffener on TIER 3 deck is approximated from the 70 x 40 IT from the Pc No 2 on Drawing No. 1811/2-201 Rev D.

4 2 2 The properties are: IA = 99.9 cm A = 11.23 cm σel = 426.3 N/mm

The stresses calculated above, along with appropriate factors of safety, will be used to check the buckling capacity of the ship structure subjected to the ABS and DNV loads required for the conversion.

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6.2.3 Hull Girder Subjected to ABS Conversion Design Primary Loads

In accordance with ABS practice, the allowable stress for an aluminum alloy subjected to primary hull girder bending loads, is given by the following formula:

Allowable stress = fp = 0.9 x (fp/Q)

2 Where: fp = the allowable stress for mild steel = 175 N/mm , 25,380 psi Q = 0.9 + q5 but not less than Q0 2 q5 = 115/σy N/mm , 17,000/σy psi 2 Q0 = 635/(σy + σu) kN/mm , 92,000/(σy + σu) psi 2 σy = minimum yield strength of unwelded aluminum in N/mm , psi 2 σu = minimum ultimate strength of welded aluminum in N/mm , psi

The material properties and allowable stresses for use in the ABS equation are presented in Table 6-5 (Metric) and Table 6-6 (English). Table 6-7 presents a comparison of the ABS and DNV allowable stresses for primary hull girder consideration. It is noted that the ABS allowable stresses are greater than the DNV allowable stresses.

Table 6-5. ABS Material Properties for Primary Bending – Metric Units

Material σy unwelded σu welded q5 Q Q0 fp N/mm2 N/mm2 N/mm2 5083-H116/H321 213.7 275.8 0.538 1.438 1.297 109.5 5086-H116/H32 193.1 241.3 0.596 1.496 1.462 105.3 5383-H116/H321 NA NA NA NA NA NA 6061-T6 241.3 137.9 0.477 1.377 1.675 114.4 6082-T6 NA NA NA NA NA NA

Table 6-6. ABS Material Properties for Primary Bending – English Units

Material σy unwelded σu welded q5 Q Q0 fp psi psi psi 5083-H116/H321 31,000 40,000 0.548 1.448 1.296 15,775 5086-H116/H32 28,000 35,000 0.607 1.507 1.460 15,158 5383-H116/H321 NA NA NA NA NA NA 6061-T6 35,000 20,000 0.486 1.386 1.673 16,481 6082-T6 NA NA NA NA NA NA

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Table 6-7. ABS & DNV Hull Girder Allowable Stresses - Primary Bending

Material DNV Filler Metal DNV Factor, f1 DNV Allowable ABS Allowable N/mm2 N/mm2 5083 H116, H321 5356 0.53 92.8 109.5 H116, H321 5183 0.60 105.0 5086, H116, H32 5356-5183 0.42 73.5 105.3 5383 H116 5183 0.64 112.0 NA 6061-T6 5356-5183 0.48 84.0 114.4 6082-T6 5356-5183 0.48 84.0 NA

6.2.3.1 ABS Vertical Bending Moment

From Table 6-3 it is seen that the largest ABS vertical bending moment acting on the vessel in accordance with the ABS Rules is 161,123 kN-m. Using the hull girder properties from Table 6-1 results in the following stresses acting on the hull girder:

Stress at Strength Deck = (161,123/3,468,558) x 1000 = 46.45 N/mm2 Stress at Keel = (161,123/3,257,532) x 1000 = 49.46 N/mm2

The actual stresses are well within the allowable stresses defined in Table 6-5. Similarly, these stresses are lower than the ABS allowable buckling stress for longitudinal bending, 82.0 N/mm2.

6.2.3.2 ABS Minimum Hull Girder Requirements

As demonstrated above, the actual stresses resulting from vertical bending are within the allowable stresses defined for ABS. In addition to the allowable stresses, ABS also has minimum hull girder property requirements. These are shown in Table 6-8 and also confirm that the conversion would be acceptable for vertical bending moment when compared to the actual hull girder properties shown in Table 6-1. In accordance with the ABS definitions used for this project, the following requirements are determined from ABS 3-2-1:

Table 6-8. ABS Minimum Hull Girder Requirements for Vertical Bending

Required Minimum Section Required Minimum Inertia Modulus cm2 - m2 cm2 - m NAVAL & COASTAL, 15,905.98 124,866 Full Speed NAVAL & COASTAL, 13,083.95 102,712 Survival

6.2.3.3 ABS Transverse Bending Moment

From Table 6-3 it is seen that the largest ABS transverse bending moment acting on the vessel in accordance with the ABS Rules is 127,636 kN-m. Using the hull girder properties from Table 6-2 results in the following stresses acting on the hull girder:

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Stress at Strength Deck = (127,636/6,068,573) x 1000 = 21.03 N/mm2 Stress at Wet Deck = (127,636/12,527,680) x 1000 = 10.19 N/mm2

ABS 3-5-3 defines the allowable primary transverse bending stress as 0.66σy welded, which from Table 6-5 (Table 6-6) has a minimum value of 193.1 N/mm2 (28,000 psi). This results in an allowable stress of 127.4 N/mm2, demonstrating the acceptable stress levels for transverse bending. Similarly, the allowable buckling stress for ABS transverse bending was determined as 27.16 N/mm2, showing acceptability of the conversion for transverse buckling.

6.2.4 Hull Girder Subjected to DNV Conversion Design Primary Loads

From Table 6-3 it is seen that the largest DNV vertical bending moment acting on the vessel in accordance with the DNV Rules is 245,774 kN-m. Using the hull girder properties from Table 6-1 results in the following stresses acting on the hull girder:

Stress at Strength Deck = (245,774/3,468,558) x 1000 = 70.86 N/mm2 Stress at Keel = (245,774/3,257,532) x 1000 = 75.45 N/mm2

From Table 6-7 it is seen that the strength deck satisfies all allowable stresses but the stress at the keel is marginally unacceptable if it is fabricated from 5086 material. If the keel is fabricated from 5083 or 5383, then the stress is acceptable.

At worst, the section modulus to the keel would have to be increased slightly to satisfy the allowable stress criteria. The increase in section modulus would be ((75.45 – 73.5)/73.5)) x 100 = 2.66% in order to reduce the bending stress to the allowable level. The new section modulus required at the keel becomes:

3 SMDNV Keel = 1.0266 x 3,257,532 = 3,344,182 cm

Obviously, this is not a significant increase and could be accommodated through some minor structural modifications that could include replacement of bottom shell plate with heavier plating or replacement of bottom shell stiffening with heavier stiffening. It is possible that heavier plate and stiffening will be required to satisfy the slam load requirements and that these increased scantlings will also increase the hull girder inertia/section modulus sufficiently so that it will not be necessary to replace any additional structure for primary hull girder considerations. Calculations presented below will determine the conversion requirements to satisfy the slam loads and the subsequent impact to hull girder strength.

From DNV 3-3-10/102 the allowable buckling stress for the bottom plate has to be reduced by a factor of η = 0.9 resulting in an allowable buckling stress at the keel of 76.11 x 0.9 = 68.50 N/mm2. This exceeds the stress at the keel calculated above by approximately 10% and represents a more critical overstress than the nominal stress calculated above. Again, the results of the slam load calculations will determine if any additional structure is required at the bottom of the ship and its impact on hull girder properties before any recommendations to solve this specific problem are addressed.

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The allowable buckling stress at the deck does not have to be reduced, i.e., DNV defines η = 1.0 for the deck resulting in an allowable buckling stress to the deck of 76.11 N/mm2 compared to the actual stress of 70.86 N/mm2.

6.2.5 DNV Transverse Bending Moment

From Table 6-3 it is seen that the largest DNV transverse bending moment acting on the vessel in accordance with the DNV Rules is 130,527 kN-m. Using the hull girder properties from Table 6-2 results in the following stresses acting on the hull girder:

Stress at Strength Deck = (130,527/6,068,573) x 1000 = 21.51 N/mm2 Stress at Wet Deck = (130,527/12,527,680) x 1000 = 10.42 N/mm2

DNV 3-3-4/E100 defines typically acceptable stresses for transverse hull girder strength. The allowable normal stress is 160f1. Table 6-4 shows the minimum value for f1 for this design as f1 = 0.42 resulting in an allowable normal stress of 67.2 N/mm2, well above the actual stresses predicted for transverse bending. Similarly, these stresses are lower than those that have already been determined as acceptable for compressive buckling considerations in accordance with DNV criteria, i.e., 27.16 N/mm2.

6.2.6 Global Loads – Torsional and Pitch Connecting Moments

A clarification of the terminology used by ABS and DNV needs to be provided for these quantities. DNV 3-1-3/B300, Figure 7 is copied below and shown in Figure 6-1. It provides clear definition for both torsional and pitch connecting moments. The torsional moment acts about the longitudinal axis of the ship and is typically a concern in monohulls with large deck openings. The pitch connecting moment refers to the action of the ship where the bow of one hull is pitching up while the other pitches down, or vice versa.

Figure 6-1. DNV Torsional & Pitch Connecting Moments from DNV 3-1-3/B300

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The ABS torsional moment accounts for the same vessel motion as the DNV pitch connecting moment. ABS does not include the action of a torsional moment about the longitudinal axis of the ship in their nominal design criteria for twin-hulled craft.

With the relatively large hull girder offered by PacifiCat it is not expected that either of these quantities will govern the design. Regardless, proper calculation of the stresses acting in the hull girder as a result of the pitch connecting or torsional moments requires the development of a full ship finite element analysis, which is outside the scope of this project. The relatively light strength deck plate (TIER 3 deck) is only 3.70 mm thick and raises the concern of its stability under the combined shear and compressive forces that would be acting when the ship is subjected to pitch connecting or combined pitch connecting and vertical bending load cases. This analysis would be required if the actual conversion were to be completed.

6.3 STRUCTURAL MODIFICATIONS FROM SECONDARY SLAM LOADS

Secondary slam loads factor into the design of numerous locations around the vessel. In accordance with the ship structural drawings there are a variety of different plate and stiffener profiles that resist these loads as a function of location. These structural combinations are listed in Table 6-9. Figure 6-2 provides a Key Plan for the slam load locations throughout the ship. The Main Vehicle Deck is shown in Figure 6-2 as a point of reference. There are no slam loads acting on the Main Vehicle Deck.

Table 6-9 includes a column for the section modulus of the plate/stiffener combination resisting the slam load. The section modulus is calculated assuming an effective breadth of plate equal to the stiffener spacing at the location under consideration. This reflects typical commercial practice and the shear lag phenomenon associated with secondary bending, i.e., bending under a normal load (the load is perpendicular to the plate). In virtually all instances, using the stiffener spacing as the effective breadth of plate produces the same results that would have been obtained using the US Navy post-buckling approach to effective width of flange. For aluminum in these calculations the effective width would have been taken as 35t, i.e., the effective width of the plate flange is equal to 35 times the thickness of the plating to which the stiffener is welded. Because the stiffener spacing throughout most of the ship is relatively tight the product of 35t equals or exceeds most stiffener spacings, the T3 strength deck is an exception. This would result in the same plating flange and mechanical properties for the plate/stiffener combination using either approach. In no case does the effective breadth used for the calculations exceed the stiffener spacing. It was not possible to get the properties for the 185 x 35 bulb or 150 x 55 IT. Since these are among the stronger sections and the calculations for these areas did not result in severe requirements it is not expected that they would need replacement.

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Table 6-9. Secondary Stiffeners Subjected to Slam Load

Location on ship Scantlings Section Modulus Effective Breadth cm3 mm Wet Deck 185 x 35 Bulb Flat on NA 230 Bow to Frame 60 10 mm plate Wet Deck 120 x 50 IT on 7 mm 67.2 230 Frame 60 to Transom plate Hull Bottom 120 x 50 IT on 20 mm 78.2 240 Bow to Frame 69 plate Hull Bottom 140 x 50 IT on 12 mm 99.2 270 Frame 69 to Frame 55 plate Hull Bottom 140 x 50 IT on 8 mm 94.5 270 Frame 55 to Frame 43 plate Hull Bottom 150 x 55 IT on 8 mm 104.1* 270 Frame 43 to Frame 31 plate Hull Bottom 140 x 50 IT on 8 mm 94.5 270 Frame 31 – Aft plate Inner Hull 120 x 50 IT on 16 mm 75.6/78.7 270 Bow to Frame 73 & 20 mm plate Inner Hull 80 x 40 IT on 8 mm & 28.8/30.5 270 Frame 73 – Aft 12 mm plate Inner Hull 70 x 40 IT on 8 mm & 23.8/24.4 270 Frame 73 – Aft 10 mm plate Haunch 185 x 35 Bulb Flat on NA NA Bow to Frame 60 10 mm plate Haunch 120 x 50 IT on 10 mm 69.9 210 Frame 60 – Aft plate Outer Hull 120 x 50 IT on 8 mm, 69.0/71.0 270 Bow to Frame 53 10 mm, 12 mm & 16 72.5/75.6 mm plate Outer Hull 80 x 40 IT on 6 mm 27.9 270 Frame 53 – Aft plate Outer Hull 70 x 40 IT on 6 mm 23.0 270 Frame – 53 Aft plate *Since there was no information on the drawings which could be used to determine the web and flange dimensions for the these profiles, the same section was used as the 140 x 50 IT with the depth of the web increased by 10 mm.

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Main Vehicle Deck

Haunch Wet Deck Outer Hull

Inner Hull

Hull Bottom Hull Bottom Keel

Figure 6-2. Key Plan for Stiffener Locations Subjected to Slam Loads

6.3.1 Slam Loads Used for Calculations

Earlier in this report a variety of calculations and tables were presented for slam loads under different vessel classing scenarios. These corresponded to ABS classing requirements for Coastal Naval Craft and Naval Craft, which were taken to correspond to DNV service area restrictions R1 and unrestricted, respectively. Slam loads were also presented for the original PacifiCat designed to its R4 service restrictions. The calculations developed for this report will only investigate the most severe ABS and DNV scenarios, i.e., ABS Naval Craft and DNV unrestricted slam loads in the operational condition. For ease of reference, the tables containing these loads (Table 5-4 and Table 5-11), along with the table containing the original R4 loads (Table 5-18) are repeated below in Table 6-10, Table 6-11, and Table 6-12, respectively.

The original intent to increment the structural modifications for slam loads from R4 to R1 and then from R1 to Unrestricted was not required by the SOW for this project and it has been decided that this intermediate step is no longer necessary. This was further justified by the lack of any structural modifications resulting from the primary hull girder loads required for the conversion from R4 to Unrestricted.

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Table 6-10. ABS Slam Loads for Naval Craft Operational & Survival Conditions

All pressures are kN/m2

Naval Craft Operational Naval Craft Survival Location Bottom Side & Wet Deck Bottom Side & Wet Deck Slamming Transom Slamming Slamming Transom Slamming Slamming Slamming 1 243.3 94.05 138.3 171.0 66.09 67.6 2 235.4 91.00 138.3 170.3 65.84 67.6 3 227.5 87.95 138.3 169.6 65.58 67.6 4 219.6 84.90 55.3 169.0 65.33 27.0 5 211.7 81.85 55.3 168.3 65.07 27.0 6 203.8 78.80 55.3 167.7 64.82 27.0 7 195.9 75.75 55.3 167.0 64.56 27.0 8 226.3 75.75 55.3 192.9 64.56 27.0 9 265.0 75.75 55.3 225.9 64.56 27.0 10 293.9 75.75 62.2 250.5 64.56 30.4 11 293.9 75.75 69.2 250.5 64.56 33.8

Table 6-11. DNV Slam Loads for Unrestricted Operational & Survival Conditions

All pressures are kN/m2

Unrestricted Operational Unrestricted Survival Location Bottom Side & Wet Deck Bottom Side & Wet Deck Slamming Transom Slamming Slamming Transom Slamming Slamming Slamming 1 601.3 103.6 262.4 251.0 103.6 89.3 2 601.3 97.1 262.4 251.0 97.1 89.3 3 601.3 90.6 262.4 251.0 90.6 89.3 4 601.3 84.1 262.4 251.0 84.1 89.3 5 601.3 77.6 131.2 251.0 77.6 44.6 6 601.3 71.2 131.2 251.0 71.2 44.6 7 541.2 71.2 131.2 225.9 71.2 44.6 8 630.2 71.2 131.2 263.1 71.2 44.6 9 717.7 71.2 131.2 299.6 71.2 44.6 10 721.6 71.2 131.2 301.2 71.2 44.6 11 601.3 71.2 131.2 251.0 71.2 44.6

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Table 6-12. DNV Secondary Slam Load Pressures for R4 Notation

All pressures are kN/m2

As seen in Table 6-10 and Table 6-11 the operational slam loads are always more severe than the survival slam loads and will be taken to govern the design. No calculations for the survival condition will be developed for this report.

6.3.2 ABS Structure to Resist Slam Loads

These calculations shall be further subdivided for plates and stiffeners.

6.3.2.1 ABS Plating to Resist Slam Loads

In accordance with ABS HSNC 3-2-3/1.3, plating subjected to lateral loading is designed in accordance with the following formula:

pk t = s (mm) 1000σ a

Where: s = stiffener spacing, mm p = design pressure, kN/m2 k = plate panel aspect ratio factor from ABS 3-2-3/Table 1 2 σa = design stress, N/mm from ABS 3-2-3/Table 2

For all instances, the factor k resulting for this design is k = 0.5.

From ABS 3-2-3/Table 2 the design stress, σa, is taken as:

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• Bottom Shell σa = 0.90σy • Side Shell σa = 0.90σy • Wet Deck σa = 0.90σy

Where σy is taken as the welded yield strength of aluminum. Also, for bottom shell outside of 0.4L, the design stress may be taken as σy.

In accordance with INCAT Designs Dwg 1811/2-201 the structure subjected to slam loads, Figure 6-2, could be a variety of different aluminum alloys/tempers. Once again, specific definition was not available for this project and the calculations shall be presented assuming 5083 and 5086. Using the strength data from ABS Table 3.3.2 presents the following material strengths:

2 • 5083-H116(H321) - σy welded = 24,000 psi = 165.5 N/mm 2 • 5086-H32(H116) - σy welded = 19,000 psi = 131.0 N/mm

There is a strong possibility that the actual ship was fabricated using 5383, a new aluminum alloy developed specifically for marine applications. It is recognized that the strength of this material is very similar to 5083 and any results would be similar for these two alloys.

The results of the ABS plate calculations for slam load are summarized in Table 6-13. In all the tables that follow for the adequacy of plate and stiffening, inadequate existing structure is shown in a red, bold font.

Table 6-13. ABS Naval Craft Operational Slam Loads – New Hull Plating Requirements & Existing Thicknesses

Location Bottom Bottom Bottom Side Side Plate Side Wet Wet Deck Wet Slam Plate Plate Slam Reqd Plate Deck Plate Deck kN/m2 Reqd Actual kN/m2 5083/5086 Actual Slam Reqd Plate 5083/5086 mm mm mm kN/m2 5083/5086 Actual mm mm mm 1 NA NA NA NA NA NA NA NA NA 2 235.4 6.40/7.19 20 91.00 4.72/5.30 16 138.3 4.96/5.57 10 3 227.5 6.29/7.07 12 87.95 4.64/5.21 10 138.3 4.96/5.57 10 4 219.6 7.33/8.24 12 84.90 4.56/5.12 10 55.3 3.13/3.52 10 5 211.7 7.20/8.09 8 81.85 4.48/5.03 8 55.3 3.13/3.52 7 6 203.8 7.06/7.94 8 78.80 4.39/4.94 6 55.3 3.13/3.52 7 7 195.9 6.92/7.78 8 75.75 4.31/4.84 6 55.3 3.13/3.52 7 8 226.3 7.44/8.36 8 75.75 4.31/4.84 6 55.3 3.13/3.52 7 9 265.0 7.64/8.59 12 75.75 4.31/4.84 6 55.3 3.13/3.52 7 10 293.9 8.05/9.04 14 75.75 4.31/4.84 10 62.2 3.32/3.74 7 11 NA NA NA NA NA NA NA NA NA

As seen in Table 6-13, the only plate that would need to be replaced are two local areas of bottom shell, which are nominally overstressed if they are fabricated from 5086 aluminum. All other existing PacifiCat bottom shell, side shell and Wet Deck plating is adequate to resist the slam loads predicted by the ABS HSNC rules for unrestricted, open-ocean operation.

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6.3.2.2 ABS Stiffener Requirements to Satisfy Slam Loads

The nominal stiffening requirements need to satisfy ABS 3-2-4/1.3.1 for section modulus:

83.3psl 2 SM = (cm3) σ a and ABS 3-2-4/1.3.2 for moment of inertia:

260 psl 3 I = (cm4) K 4 E

Where: s = stiffener spacing, m l = stiffener span, m K4 = 0.0021 for shell and deep tank stringers and transverse webs constructed of aluminum = 0.0018 for deck girders and transverses constructed of aluminum E = modulus of elasticity = 6.9 x 104 N/mm2 for aluminum p is the same as defined above. The design stress, σa, is assigned different values than used for plate analysis. These values are taken from ABS 3-2-4/Table 1 and are summarized below for use in this project. All values reflect the slam load condition.

• Bottom longitudinal σa = 0.65σy • Side longitudinal σa = 0.60σy • Wet Deck longitudinal σa = 0.75σy

Where: σy can be taken as above, Section 6.3.2.1, for welded aluminum

The results of the ABS slam load requirements for stiffener section modulus and inertias are summarized in Table 6-15 and Table 6-16, respectively. Table 6-14 presents a summary of the ABS allowable secondary stresses.

Table 6-14. Summary of ABS Allowable Secondary Bending Stresses

ABS 5083 5086 5083 5086 (N/mm2) (N/mm2) (psi) (psi) Bottom Shell Plate 149 118 21,600 17,100 Stiffener 107.6 85.2 15,600 12,350 Side Shell Plate 149 118 21,600 17,100 Stiffener 99.3 78.6 14,400 11,400 Wet Deck Plate 149 118 21,600 17,100 Stiffener 124.1 98.3 18,000 14,250 Note: * This table does not include the higher allowable stresses for bottom shell plate outside of 0.4L.

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Table 6-15. ABS Naval Craft Operational Slam Loads– Section Modulus Requirements & Existing Strength

Location Bottom Bottom SMreqd Bottom SM Side Side SMreqd Side SM Wet Deck Wet Deck SMreqd Wet Deck Slam 5083/5086 Actual Slam 5083/5086 Actual Slam 5083/5086 SM Actual kN/m2 cm3 cm3 kN/m2 cm3 cm3 kN/m2 cm3 cm3 1 NA NA NA NA NA NA NA NA NA 2 235.4 63.0/79.6 78.2 91.00 29.68/37.50 72.5 138.3 30.7/38.8 NA 3 227.5 60.9/76.9 99.2 87.95 28.69/36.24 72.5 138.3 30.7/38.8 NA 4 219.6 66.1/85.5 99.2 84.90 27.69/34.98 72.5 55.3 12.3/15.5 67.2 5 211.7 63.7/80.5 94.5 81.85 26.70/33.73 27.9 55.3 12.3/15.5 67.2 6 203.8 61.4/77.5 104.1 78.80 25.70/32.47 27.9 55.3 12.3/15.5 67.2 7 195.9 59.0/74.5 94.5 75.75 24.71/31.21 27.9 55.3 12.3/15.5 67.2 8 226.3 68.1/86.1 94.5 75.75 24.71/31.21 27.9 55.3 12.3/15.5 67.2 9 265.0 79.8/100.8 99.1 75.75 24.71/31.21 27.9 55.3 12.3/15.5 67.2 10 293.9 88.5/111.8 101.3 75.75 24.71/31.21 27.9 62.2 13.8/17.5 67.2 11 NA NA NA NA NA NA NA NA NA

Table 6-16. ABS Naval Craft Operational Slam Loads– Inertia Requirements & Existing Strength

Location Bottom Bottom Ireqd Bottom I Side Side Ireqd Side I Wet Deck Wet Deck Ireqd Wet Deck Slam cm4 Actual Slam cm4 Actual Slam cm4 I Actual kN/m2 cm4 kN/m2 cm4 kN/m2 cm4 1 NA NA NA NA NA NA NA NA NA 2 235.4 175.2 885 91.00 76.2 757 138.3 98.6 NA 3 227.5 169.3 1164 87.95 73.6 757 138.3 98.6 NA 4 219.6 183.8 1164 84.90 71.1 757 55.3 39.4 606 5 211.7 177.2 1014 81.85 68.5 187 55.3 39.4 606 6 203.8 170.6 1187 78.80 66.0 187 55.3 39.4 606 7 195.9 164.0 1014 75.75 63.4 187 55.3 39.4 606 8 226.3 189.5 1014 75.75 63.4 187 55.3 39.4 606 9 265.0 221.9 1164 75.75 63.4 187 55.3 39.4 606 10 293.9 246.0 1225 75.75 63.4 187 62.2 44.4 606 11 NA NA NA NA NA NA NA NA NA

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6.3.2.3 ABS Structure Required to Satisfy Slam Load Criteria

Table 6-16 shows that all of the existing stiffening satisfies the ABS inertia requirements while Table 6-15 shows that some of the existing stiffening on the bottom shell and side shell would have to be replaced if it’s fabricated out of 5086 aluminum. Close investigation of the undersized stiffening identified in Table 6-15 reveals that the existing stiffeners are only nominally undersized compared to the new requirements. The most undersized stiffeners are at Location 10 on the bottom shell, which are currently 140 x 50 I/T. The new, required section modulus is only 10.5 cm3 (0.65 in3) greater than the capacity of the existing stiffener. The overstressed stiffener, 140 x 50 I/T has a 50 mm x 4 mm (2” x 0.157”) flange and the actual modifications to this structure could be accomplished by welding a 32 mm x 6 mm (1.25” x 0.236”) doubler to the existing flange. This increases the section modulus from 101.3 cm3 (6.2 in3) to 114.1 cm3 (7.0 in3), satisfying the required section modulus criteria of 111.8 cm3. This represents the most severe modification that would have to be applied, all others being even less severe. In addition, it is also noted that the doubler added to the flange would only need to be applied to the local portion of the stiffener that is overstressed, i.e., the entire span of the stiffener is not overstressed and more detailed calculation would quickly reveal that only a small portion of the overstressed stiffener spans would have to be reinforced with flange doublers. The cost estimates developed for this project will assume the entire span of the stiffener has the doubler added.

As noted in Table 6-15 and Table 6-16, there is only minimal stiffening that would need reinforcement along the bottom shell, side shell or Wet Deck to satisfy the ABS HSNC criteria for open-ocean operation. Most of the existing stiffeners throughout these areas are acceptable. The original PacifiCat structure was designed to satisfy DNV R4 service area restrictions, a classification that requires the craft never be more than 20 nautical miles from safe harbor. Combined with the earlier results for global loads and shell plate subjected to slam loads, it is a surprising and unexpected result that the structure for this craft is essentially acceptable to operate in the open-ocean, unrestricted environment in accordance with the criteria presented in the ABS HSNC, requiring only minimal modification.

All of the ABS structural modifications are shown on the drawings included in this report. In summary, the ABS modifications to resist the slam loads are:

• Increase a portion of the bottom hull plate from 8mm to 9mm plate. • Add 32mm x 6mm flange doublers throughout a few forward and aft stiffeners. • Add 25mm x 6mm flange doublers from Frame 48 aft on the inner side shell and outer side shell stiffeners.

All structural modifications assume the use of the stronger alloy, 5083.

6.3.2.4 Weight Estimate of ABS Structural Modifications for Slam Loading

The following weight estimate, summarized in Table 6-17, is associated with the ABS structural modifications discussed above. All plate areas where electronically measured off the AutoCad drawings available for the ship. The stiffener lengths were estimated from these same drawings

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with approximations for stiffener termination points to simplify the weight impacts for the purposes of this project.

Table 6-17. Weight Increase to Accommodate ABS Structural Modifications – Open-Ocean, Unrestricted

Component Existing Structure Weight of New Structure Weight of Weight Existing New Increase Structure Structure (kg) (kg) (kg) Bottom shell 288.44 m2 @ 8mm 6265 288.44 m2 @ 9mm 7048 783.0 plate, P/S Bottom Shell 140 x 50 I/T in both 3284 140 x 50 I/T in both 3284* 0 Stiffening IWO locations locations Removed Plate Bottom Shell Remains Unchanged N/A 432 meters of 32mm x 225 225 stiffening, P/S 6mm flange doubler Outer hull Remains Unchanged N/A 2030 meters of 25mm 827 827 stiffening, P/S x 6mm flange doubler Inner hull Remains Unchanged N/A 1320 meters of 25mm 538 538 stiffening, P/S x 6mm flange doubler Σ 2373 *The new stiffening on the new plate will be the same as the existing stiffening on the removed plate, i.e., no weight change for the stiffening component.

The results presented in Table 6-17 indicate a total structural weight increase of just over 2 metric tonnes to accommodate the ABS structural modifications.

6.3.3 DNV Structure to Resist Slam Loads

These calculations shall be further subdivided for plates and stiffeners.

6.3.3.1 DNV Plating to Resist Slam Loads

In accordance with DNV HSLC & NSC 3-3-5/B300, the hull plate subjected to slam loads needs to satisfy the following:

22.4k s p t = r sl (mm) σ sl

where: kr = correction for curved plates = (1-0.5(s/r)) s = stiffener spacing, m 2 psl = slam pressure from 3-1-2, kN/m 2 σsl = allowable bending stress due to lateral load, N/mm

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The slam pressures are shown above in Table 6-11, again using only the operational slam loads for these calculations since they govern in all instances compared to survival. The allowable stresses are taken from DNV 3-3-5/Table A1 with only the appropriate values shown below:

• Bottom plate σsl = 200f1 • Side plate σsl = 180f1 • Wet Deck plate σsl = 200f1

The values for f1 are summarized below and are the same as those shown above in Table 6-4.

• 5083; f1 = 0.60 • 5086; f1 = 0.42 • 5383; f1 = 0.64

Similar to PacifiCat Dwg 1811/2-201, the strength for 5383 is slightly less than, but similar to 5083. As a result, all the calculations for DNV slam loads will only be done for 5083 and 5086, the same as ABS.

The allowable bending stresses, based on welded properties, will be used for the plate design:

• 5083 0.60 x 200 = 120 N/mm2 for Bottom & Wet Deck plate 0.60 x 180 = 108 N/mm2 for Side plate

• 5086 0.42 x 200 = 84 N/mm2 for Bottom & Wet Deck plate 0.42 x 180 = 75.6 N/mm2 for Side plate

The results of these calculations are presented in Table 6-18.

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Table 6-18. DNV Unrestricted Operation Slam Loads– New Hull Plating Requirements & Existing Thicknesses

Location Bottom Bottom Bottom Side Side Plate Side Plate Wet Deck Wet Deck Plate Wet Deck Slam Plate Reqd Plate Actual Slam Reqd Actual Slam Reqd Plate kN/m2 5083/5086 mm kN/m2 5083/5086 mm kN/m2 5083/5086 Actual mm mm mm mm 1 NA NA NA NA NA NA NA NA NA 2 601.3 12.03/14.38 20 97.1 5.76/6.88 16 262.4 7.62/9.11 10 3 601.3 12.03/14.38 12 90.6 5.56/6.65 10 262.4 7.62/9.11 10 4 601.3 13.54/16.18 12 84.1 5.36/6.40 10 262.4 7.62/9.11 10 5 601.3 13.54/16.18 8 77.6 5.15/6.15 8 131.2 5.39/6.44 7 6 601.3 13.54/16.18 8 71.2 4.91/5.87 6 131.2 5.39/6.44 7 7 541.2 12.84/15.35 8 71.2 4.91/5.87 6 131.2 5.39/6.44 7 8 630.2 13.86/16.57 8 71.2 4.91/5.87 6 131.2 5.39/6.44 7 9 717.7 14.79/17.68 12 71.2 4.91/5.87 6 131.2 5.39/6.44 7 10 721.6 14.83/17.73 14 71.2 4.91/5.87 10 131.2 5.39/6.44 7 11 NA NA NA NA NA NA NA NA NA

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6.3.3.2 DNV Stiffener Requirements to Satisfy Slam Loads

In accordance with DNV 3-3-5/C201, stiffeners subjected to slam loads shall satisfy the following criteria for section modulus, Z, and shear area, As:

ml 2 sp Z = sl (cm3) σ sl

6.7(l − s)sp A = sl (cm2) s τ where: m = factor from DNV Table C1 = 85 for side, bottom and deck longitudinal members l = stiffener span, m s = stiffener spacing, m 2 psl = design slam pressure, kN/m 2 σsl = allowable bending stress, =180f1, N/mm τ = τsl = allowable shear stress = 90f1 for slam load considerations

The allowable stresses become:

2 • 5083 σsl = 0.60 x 180 = 108 N/mm 2 τsl = 0.60 x 90 = 54 N/mm

2 • 5086 σsl = 0.42 x 180 = 75.6 N/mm 2 τsl = 0.42 x 90 = 37.8 N/mm

The calculations for section modulus and shear area are presented in Table 6-20 and Table 6-21, respectively. Table 6-19 presents a summary of the DNV allowable secondary bending stresses.

Table 6-19. Summary of DNV Allowable Secondary Bending Stresses

DNV 5083 5086 5083 5086 (N/mm2) (N/mm2) (psi) (psi) Bottom Shell Plate 120 84 17,400 12,180 Stiffener 108 75.6 15,660 10,960 Side Shell Plate 108 75.6 15,660 10,960 Stiffener 108 75.6 15,660 10,960 Wet Deck Plate 120 84 17,400 12,180 Stiffener 108 75.6 15,660 10,960

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Table 6-20. DNV Unrestricted Operation Slam Loads– Section Modulus Requirements & Existing Strength

Location Bottom Bottom SMreqd Bottom SM Side Side SMreqd Side SM Wet Deck Wet Deck SMreqd Wet Deck Slam 5083/5086 Actual Slam 5083/5086 Actual Slam 5083/5086 SM Actual kN/m2 cm3 cm3 kN/m2 cm3 cm3 kN/m2 cm3 cm3 1 NA NA NA NA NA NA NA NA NA 2 601.3 163.6/233.7 78.2 97.1 29.8/42.6 72.5 262.4 68.4/97.7 NA 3 601.3 163.6/233.7 99.2 90.6 27.8/39.8 72.5 262.4 68.4/97.7 NA 4 601.3 184.0/262.9 99.2 84.1 25.8/36.9 72.5 262.4 68.4/97.7 67.2 5 601.3 184.0/262.9 94.5 77.6 23.9/34.1 27.9 131.2 34.2/48.9 67.2 6 601.3 184.0/262.9 104.1 71.2 21.8/31.1 27.9 131.2 34.2/48.9 67.2 7 541.2 165.6/236.6 94.5 71.2 21.8/31.1 27.9 131.2 34.2/48.9 67.2 8 630.2 192.8/275.5 94.5 71.2 21.8/31.1 27.9 131.2 34.2/48.9 67.2 9 717.7 219.6/313.7 99.1 71.2 21.8/31.1 27.9 131.2 34.2/48.9 67.2 10 721.6 220.8/315.4 101.3 71.2 21.8/31.1 27.9 131.2 34.2/48.9 67.2 11 NA NA NA NA NA NA NA NA NA

Table 6-21. DNV Unrestricted Operation Slam Loads– Shear Area Requirements & Existing Strength

Location Bottom Bottom As Bottom As Side Side As Side As Wet Deck Wet Deck As Wet Deck Slam Reqd Actual Slam Reqd Actual Slam Reqd As Actual kN/m2 cm2 cm2 kN/m2 cm2 cm2 kN/m2 cm2 cm2 1 NA NA NA NA NA NA NA NA NA 2 601.3 17.2/24.6 7.8 97.1 3.0/4.3 7.8 262.4 7.3/10.4 NA 3 601.3 17.2/24.6 10.5 90.6 2.8/4.0 7.8 262.4 7.3/10.4 NA 4 601.3 18.7/26.8 10.5 84.1 2.6/3.8 7.8 262.4 7.3/10.4 7.8 5 601.3 18.7/26.8 10.5 77.6 2.4/3.5 3.6 131.2 3.6/5.2 7.8 6 601.3 18.7/26.8 10.6 71.2 2.2/3.2 3.6 131.2 3.6/5.2 7.8 7 541.2 16.9/24.1 10.5 71.2 2.2/3.2 3.6 131.2 3.6/5.2 7.8 8 630.2 19.6/28.1 10.5 71.2 2.2/3.2 3.6 131.2 3.6/5.2 7.8 9 717.7 22.4/31.9 10.5 71.2 2.2/3.2 3.6 131.2 3.6/5.2 7.8 10 721.6 22.5/32.1 10.5 71.2 2.2/3.2 3.6 131.2 3.6/5.2 7.8 11 NA NA NA NA NA NA NA NA NA

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6.3.3.3 DNV Structure Required to Satisfy Slam Load Criteria

As shown in Table 6-18, Table 6-20 and Table 6-21 by the red, bold inputs, there are a number of plate thickness and stiffener requirements that are not satisfied by the existing structure for a DNV open-ocean, unrestricted notation. Most of the problems are in the bottom hull although there are a few areas of concern in the side shell and Wet Deck.

Again, all structural modifications will be made using the stronger aluminum alloy, 5083, with no structural modifications developed for 5086.

All of the DNV structural modifications are shown on the drawings included in this report. In summary, the DNV modifications to resist the slam loads are:

• Increase a significant percentage of the bottom hull plate from 8mm, 10mm or 12mm to 14mm plate. • Increase the bottom hull stiffening to 10 x 5.75#T forward of frame 8 and to 10 x 7.25#T aft of Frame 8. The requirements for shear area drove the design of these members and resulted in significantly heavier stiffening than would have been required to satisfy the section modulus criteria, which would have been satisfied with 7 x 3.5#T for all stiffening on the bottom hull. • Similar to the modifications required for the ABS Inner and Outer side shell, add 25mm x 6mm flange doublers from Frame 48 aft on the inner side shell and outer side shell stiffeners. The same flatbar doubler is also assumed for Location 4 on the Wet Deck, which is marginally overtstressed.

6.3.3.4 Increased Hull Girder Properties as a Result of New Slam Load Structure

As discussed in Section 6.2.4 above, it was necessary to increase the section modulus to the keel of the vessel to satisfy the DNV allowable stress and buckling criteria. The scantlings resulting from the conversion slam loads are significantly greater than the original scantlings with 14mm plate replacing 8mm original plate and 10 x 5.75#T stiffeners (Area = 32.2 cm2) replacing 140 x 50 IT (Area = 14.32 cm2) original stiffeners. This has a significant impact to the hull girder properties as shown in Table 6-22.

Table 6-22. Hull Girder Properties with Revised DNV Slam Required Scantlings

Property Value Value Cross Sectional Area 14,713.96 cm2 Moment of Inertia 287,695.90 cm2 m2 Section Modulus, Deck 38,769.54 cm2 m 3,876,954 cm3 Section Modulus, Keel 43,117.75 cm2 m 4,311,775 cm3 Shear Area 6273.71 cm2 NA, deck 7.42 m NA, keel 6.67 m

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From Table 6-1 it is seen that the original section modulus to the keel was 32,575.32 cm2. The new section modulus is 43,117.75 approximately 32% greater than the original strength – far greater than required by the calculations shown above to satisfy the stress and buckling criteria.

6.3.3.5 Weight Estimate of DNV Structural Modifications for Slam Loading

The following weight estimate, summarized in Table 6-23, is associated with the DNV modifications to the structure. The drawings of the bottom hull are not expanded and so the plate areas were estimated from the midship section and hull bottom drawings to approximate the required area of plate replacement. The 25 mm flat keels in the port and starboard bottom hulls was accounted for and not included in the calculation of plate area that needs to be replaced. The stiffener lengths were estimated from these same drawings with approximations for stiffener termination points to simplify the weight impacts for the purposes of this project.

Table 6-23. Weight Increase to Accommodate DNV Structural Modifications – Open- Ocean, Unrestricted

Component Existing Structure Weight of New Structure Weight of Weight Existing New Increase Structure Structure (kg) (kg) (kg) Bottom 449.5 m2 @ 8mm 9558 726.0 m2 @ 14 mm 27,016 8786 hull plate, 27.8 m2 @ 10mm 739 2 P/S 248.7 m @ 12mm 7933 Bottom 3432.0 m of 140 x 50 IT 13,064 3484.8 m of 10 x 29,822 20,001 hull 633.6 m of 150 x 55 IT 3032 5.75#T stiffening, 580.8 m of 10 x 6275 P/S 7.25#T Outer hull Remains Unchanged N/A 2030 meters of 25mm 827 827 stiffening, x 6mm flange doubler P/S Inner hull Remains Unchanged N/A 1320 meters of 25mm 538 538 stiffening, x 6mm flange doubler P/S Wet Deck Remains Unchanged N/A 441 meters of 25mm x 180 180 stiffening, 6mm flange doubler P/S Σ 30,332

As seen in Table 6-23, it requires approximately 30 metric tonnes of structural modifications to upgrade the PacifiCat to satisfy DNV open, ocean requirements. ABS requires approximately 1 metric tonne of modifications for the same notation. As discussed above, the shear requirements for DNV stiffening present governing criteria that far surpass the criteria for section modulus. ABS does not have any specific criteria for the shear area of stiffening subjected to slam loads.

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6.4 VEHICLE DECK STRUCTURE & FINITE ELEMENT ANALYSIS

As demonstrated in Section 5, it was necessary to develop various finite element analyses to confirm the vehicle deck structure in way of the different wheel loads acting on the deck. The primary purpose of the FEA is to analyze the vehicle deck plating subjected to the tire loads. Analysis is also provided for the deck stiffening but it is not proposed that the stiffeners need the FEA – their design can be accomplished using the rule procedures for both ABS and DNV.

To analyze the plate structure FEA was developed for tire footprints that have a breadth greater than the vehicle deck stiffener spacing. Of these tires, there are two basic scenarios (please refer to Figure 6-3):

1. Tire A - Tires with a breadth that is only nominally greater than the stiffener spacing,

2. Tire B - Tires with a breadth significantly greater than the stiffener spacing and, in some instances, approaching twice the stiffener spacing.

In order to determine the maximum plate bending stresses it was necessary to investigate two fundamental tire locations relative to the structural arrangement of the vehicle deck. These are shown schematically in Figure 6-3 and summarized as:

1. Tire A/Tire B centered along the length of the deck longitudinal with the centerline of the tire centered between deck longitudinals.

2. Edge of the Tire A/Tire B footprint at the end of the deck longitudinal with the centerline of the tire centered between the deck longitudinals. Transverse Floor

Tire A 1200 mm

Tire B 210 mm long’l 600 mm spacing (Typ)

Transverse Floor Figure 6-3. Tire Footprint Schematic for Plate Design on Vehicle Deck

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In order to fully analyze the vehicle deck structure, the footprints shown in Figure 6-3 had to be analyzed on both the light and heavy vehicle deck extrusions using both the ABS and DNV design accelerations. The results of these analyses are shown below.

The schematic in Figure 6-4 presents the tire footprint locations studied to investigate the stiffener requirements. These are summarized as:

1. Tire A/Tire B centered along the length of the longitudinal with the centerline of the tire aligned with a deck longitudinal. This will result in the maximum moment acting in the deck longitudinal directly under the center of the tire.

2. Edge of the Tire A/Tire B footprint at the end of the longitudinal with the centerline of the tire aligned with the deck longitudinal. This will produce the maximum shear in the stiffener.

Transverse floor

Tire A 1200 mm

Tire B 210 mm long’l 600 mm spacing (Typ)

Transverse floor

Figure 6-4. Tire Footprint Schematic for Stiffener Design on Vehicle Deck

The tire loads were analyzed for the following vehicles

• MK-48 LVS, Front Power Unit • HMMWV • LAV, Maintenance Recovery • Chassis, Trailer, General Purpose M353 (footprint fits between deck longitudinals)

As a result of the structural analysis performed for the vehicle deck a new vehicle arrangement has been developed and is shown in Figure 6-5. The vehicles are arranged to include 30 cm (approximately 12 inches) between their bumpers. The US Marine Corps [3] only require 10 inches so additional space could be reclaimed if necessary. The loadout shown in Figure 6-5 has been developed with attention to balancing the load port/starboard, i.e., the balanced MEU loadout. The trim of the vessel needs to be addressed at the time of loadout and vehicles loaded in conjunction with other factors contributing to the trim of the vessel.

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Figure 6-5. New Military Vehicle Arrangements with Transverse Floor Locations

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6.4.1 Transverse Vehicle/Tire Orientation

All analyses presented in this project investigate the requirements for the Vehicle Deck structure assuming longitudinal orientation of the vehicles on the deck. Most studies of any vehicle deck structure also include analysis for the athwartships orientation of the proposed vehicles in the loadout. There are a number of reasons why the transverse orientations have been eliminated from the studies of this project:

1. The traffic flow of vehicles on this ship is different from typical US Navy displacement vessels. The PacifiCat has centerline pillars and obstacles that make traversing this portion of the ship difficult and defines longitudinal travel lanes along the length of the ship.

2. There is no need to turn vehicles to load or off-load. Access to the Main Vehicle Deck is provided through both the bow and the stern of the ship. Vehicles can be loaded through the stern and off-loaded from the bow (or vice versa) without having to turn any vehicles.

3. Even if a design governing vehicle were to be transversely oriented it will only happen during the loading or off-loading operation, i.e., in port, not at sea where ship motion accelerations greatly increase the design loads seen by the deck structure.

Recognition of this aspect of the PacifiCat helps to minimize the work required for conversion of the ship to support military vehicles. Other HSV conversions may still require the investigation of both transverse and longitudinal orientations of the vehicles. As shown in Figure 6-5, all vehicles are longitudinally oriented.

6.4.2 Structural & Material Properties of the Main Vehicle Deck Extrusions

As discussed above, there are two basic extrusions that comprise the Main Vehicle Deck; a heavy extrusion from ship centerline to 3375 mm off centerline P/S, and a light extrusion that makes up the balance of the deck. Per INCAT DESIGNS Dwg No. 1811/2-201 Rev D, all extrusions on the ship are either 6061-T6 or 6082-T6. ABS only presents material properties for 6061-T6 and DNV uses the same f1 factor for both alloys. Both ABS and DNV note two different sets of material properties depending on the filler metal used in the welding process. All indications suggest the use of the stronger set of properties is appropriate and so that data will be used in this project.

In accordance with the ABS and DNV Rules, the allowable stresses for the Main Vehicle Deck structure subjected to wheel loads is determined as:

• ABS allowable stress, deck plate = 0.60σy from ABS 3-2-3/Table 2, where σy is the welded strength of the material.

• ABS allowable stress, stiffening = 0.33σy from ABS 3-2-4/Table 1, where σy is the welded strength of the material.

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2 Where: ABS uses a value of σy welded = 20,000 psi = 138 N/mm

• DNV allowable stress, deck plate = 180f1 • DNV allowable stress, stiffening = 160 f1

With f1 = 0.48 for both 6061-T6 and 6082-T6.

This information is used to develop the allowable stresses presented in Table 6-24, which demonstrates the higher allowable stresses used by DNV for the secondary loads/stresses in this area.

Table 6-24. ABS & DNV Allowable Stresses for Vehicle Deck Structure

ABS Allowable DNV Allowable ABS Allowable DNV Allowable Stress (6061-T6) Stress (6061-T6) Stress (6061-T6) Stress (6061-T6) (N/mm2) (N/mm2) (psi) (psi) Vehicle Deck 82.7 86.4 12,000 12,530 Plate Vehicle Deck 55.2 76.8 6600 11,140 Stiffening

The data in Table 6-25 summarizes the physical dimensions and resulting properties of the extrusions on the Vehicle Deck. The physical properties were estimated from Catamaran Ferries International Dwg No S101 Midship, Rev 0 Midship Section – Ship #3 At Frames 28 and 43, which was available as an AutoCad file. While some of the dimensions could be measured directly from the drawing, such as deck plate thickness, web thickness and breadth of flange, others had to be estimated based on other data ascertained from the drawing. For instance, the enclosed area of the stiffener was determined from the AutoCad drawing and used to determine a reasonable balance of flange and web dimensions to approximate the flange area of the stiffener. Efforts to obtain this information directly from the builder or designer were not successful.

Table 6-25. Mechanical Properties - Heavy & Light Extrusions on Vehicle Deck

Property Heavy Extrusion Light Extrusion Web Height, mm (in) 127.8 (5.032) 95.0 (3.740) Web Thickness, mm (in) 7.0 (0.276) 4.3 (0.167) Flange Breadth, mm (in) 50 (1.969) 50 (1.969) Flange Thickness, mm (in) 9.6 (0.380) 8.7 0.341) Deck Plate Thickness, mm (in) 9.8 (0.386) 8.0 (0.315) Stiffener Spacing, mm (in) 210 (8.268) 200 (7.874)

Moment of Inertia, cm4 (in4) 981 (23.6) 426.6 (10.2) Section Modulus, Flange, cm3 (in3) 93.3 (5.7) 52.9 (3.2) Section Modulus, Deck cm3 (in3) 233.2 (14.2) 137.6 (8.4)

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6.4.3 Summary of the Finite Element Models

There were two basic finite element models developed for this task, one each for the light and heavy extrusion. They are very similar and are shown below in Figure 6-6 and Figure 6-7, respectively. A very fine mesh was developed for these models in order to more easily accommodate all the different tire footprints that needed to be placed into the model. The models were built and analyzed using the FEMAP/NE NASTRAN package. The metric dimensions of the extrusions were converted into English measure for analysis using pounds and inches for all modeling and analysis. Each of the models has a breadth equal to the breadth of eight extrusions and a span of 4.8 meters, i.e., the length of four extrusions. The outer perimeter of the models is supported by simple support boundary conditions. The presence of the transverse floors, spaced at 1.2 meters, are developed in the model using simple support boundary conditions, i.e., they allow rotation about the transverse axis at the ends of the longitudinal stiffener spans and are fixed against all translation. No structure is included in either model to analyze the transverse floors, which have an upper strake of 10mm plate, 252 mm high. The upper strake of plate is supported by a 100 x 10mm flatbar that is used to land the extrusion. See discussion below on Fabrication of Main Vehicle Deck and Transverse Floors.

Deck plate = 8.0 mm

Transverse floor boundary conditions

4 spans @ 1200 mm each

8 spaces @ 200 mm each

Figure 6-6. Finite Element Model Used for Light Extrusion

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Deck plate = 9.8 mm

Transverse floor boundary conditions

4 spans @ 1200 mm each

8 spaces @ 210 mm each

Figure 6-7. Finite Element Model Used for Heavy Extrusion

6.4.4 Fabrication of Main Vehicle Deck and Transverse Floors

Although not specifically relevant to the finite element model, this is a good location to present discussion on the actual fabrication of the Main Vehicle Deck, which consists of the light and heavy extrusions discussed above and transverse floors every 1.2 meters. Each of the two extrusions has a length of 1.2 meters and is welded into the transverse floor at each end. The extrusions are intercostal between the floors, i.e., they are not continuous as typically envisioned of vehicle deck structure in a US Navy ship. The flanges of the stiffeners on the extrusion rest on the 100 x 10 mm flatbar mentioned above, which is approximately 162 mm below the upper edge of the floor. The flatbars for both extrusions are located such that the upper edge of the transverse floor is approximately 10mm above the upper surface of the extrusion, i.e., the floor “sticks up” above the deck surface enough to accommodate the weld required for the support of the extrusion. Details of this fabrication are taken from the midship section drawing, Figure 6-8, and in more detail in Figure 6-9. This implies that the upper edges of the transverse floors actually protrude above the road surface of the Main Vehicle Deck and are part of the roadway surface contacted by the vehicle tires. Figure 6-23 provides an additional close-up view of this detail.

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Area detailed in Figure 6-9

Figure 6-8. Midship Section of PacifiCat

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Upper edge of transverse floor

Vehicle Deck Surface

Main Vehicle Deck

Wet Deck

Figure 6-9. Midship Section Details IWO Main Vehicle Deck Fabrication

6.4.5 Summary of Vehicle Deck FEA Results

The finite element analyses were developed to investigate the response of the vehicle deck plate to the tire loads. It was felt that this was necessary because many of the tire footprints exceed the stiffener spacing, which violates the assumptions in the ABS deck plate formulations for wheel loaded decks. The DNV rules allow for this situation but the FEA also includes DNV accelerations and comparison to DNV allowable stresses for completeness and consistency of the work within this project.

There were a large number of analyses that were performed for this FEA work. The tire locations in Figure 6-3 and Figure 6-4 were analyzed for ABS and DNV loads on both the heavy and light extrusions. The results of all the analyses are presented below in Table 6-26 through Table 6-33.

The loads in the tables represents the static tire footprints increased by the vertical acceleration for either ABS or DNV assuming their maximum vertical accelerations, i.e., assuming the vehicle is located in the bow of the ship. As such, many of these results are conservative. These static tire footprint loads are shown in Table 5-22 and Table 5-24.

All of the FEA work was done using inch/pound units. The data available from the vehicles was all in English units and it simplified the analysis to use the English system of measure although all the ship structure is metric. The plate bending stresses are calculated in psi and converted to N/mm2 for presentation in Table 6-26 through Table 6-33.

The Load Case shown in the tables below is used as a reference for discussion of specific governing load cases. There are two numbers in each Load Case cell. The left hand number

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refers to the Load Case for the Tire @ Midspan while the right hand number refers to the Load Case for the Tire @ End of stiffener.

To summarize from above, the static footprints for each of the tires used in the analysis are:

• LAV 11” x 22” with a total tire load = 3770 pounds • HMMWV 12.5” x 14” with a total tire load = 1950 pounds • MK48 LVS 16” x 27” with a total tire load = 6830 pounds • M353 Chassis 7” x 12” with a total tire load = 1360 pounds

With extrusion properties:

• Light Extrusion: 8 mm plate with 200 mm stiffener spacing (0.315” plate with stiffener spacing = 7.87”) • Heavy Extrusion: 9.8 mm plate with 210 mm stiffener spacing (0.386” plate with stiffener spacing = 8.27”)

As such, the M353 chassis will fit between the stiffeners of both extrusions when centered on the plate. None of the other tires fit within the stiffener spacing, regardless of location.

Figure 6-10 through Figure 6-13 are provided as a few examples of some of the load input and respective output files for the plate bending stress. All of these figures provide input and results for the tire load at the center of the plate panel using ABS vertical accelerations.

The stresses shown in Table 6-26 through Table 6-33 compare directly to the allowable stresses associated with both ABS and DNV. Both rule sets define allowable stresses associated with plates subjected to normal loads. These stresses are referred to as normal bending stresses, i.e., they are oriented along the principal bending axes of the element being investigated and are parallel to the longitudinal and transverse axes of the ship. Many FEA results calculate and report the Von Mises stresses acting in plate elements. This type of stress represents different criteria than the nominal allowable stresses cited by ABS and DNV for typical design associated with rule based calculations. The stresses presented in the tables below, i.e., the “Plate Bending Stress”, are normal bending stresses parallel to the transverse axis of the ship, i.e., they are acting perpendicular to the longitudinal deck stiffeners across the short dimension of the plate panel.

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Table 6-26. ABS Load, Light Extrusion, Tire Centered on Plate

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 1/5 19.3 5941 (44.3) 5128 (41.2) HMMWV 2/6 14.1 3680 (25.4) 2848 (19.6) Mk48 LVS 3/7 19.6 5236 (36.1) 4780 (33.0) Chassis Tri GEN 4/8 20.1 5105 (35.2) 3965 (27.3) purpose m353

Table 6-27. ABS Load, Light Extrusion, Tire Centered on Stiffener

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 9/13 19.3 4210 (31.1) 3671 (29.1) HMMWV 10/14 14.1 3044 (21.0) 3852 (26.6) Mk48 LVS 11/15 19.6 5282 (36.4) 5357 (36.9) Chassis Tri GEN 12/16 20.1 2429 (16.7) 2850 (19.6) purpose m353

Table 6-28. ABS Load, Heavy Extrusion, Tire Centered on Plate

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 17/21 19.3 4171 (30.8) 3760 (28.8) HMMWV 18/22 14.1 2547 (17.6) 2049 (14.1) Mk48 LVS 19/23 19.6 3672 (25.3) 3380 (23.3) Chassis Tri GEN 20/24 20.1 3543 (24.4) 2825 (19.5) purpose m353

Table 6-29. ABS Load, Heavy Extrusion, Tire Centered on Stiffener

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 25/29 19.3 2796 (17.2) 3357 (21.9) HMMWV 26/30 14.1 2539 (17.5) 2914 (20.1) Mk48 LVS 27/31 19.6 1569 (10.8) 2163 (14.9) Chasis Tri GEN 28/32 20.1 3653 (25.2) 4787 (33.0) purpose m353

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Table 6-30. DNV Load, Light Extrusion, Tire Centered on Plate

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 33/37 37.4 11,498 (86.1) 9925 (79.8) HMMWV 34/38 27.3 7122 (49.1) 5513 (38.0) Mk48 LVS 35/39 37.9 10,133 (69.9) 9251 (63.8) Chasis Tri GEN 36/40 38.8 9880 (68.1) 7674 (52.9) purpose m353

Table 6-31. DNV Load, Light Extrusion, Tire Centered on Stiffener

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 41/45 37.4 8148 (60.2) 7105 (56.3) HMMWV 42/46 27.3 5892 (40.6) 7455 (51.4) Mk48 LVS 43/47 37.9 10,224 (70.5) 10,369 (71.5) Chasis Tri GEN 44/48 38.8 4701 (32.4) 5515 (38.0) purpose m353

Table 6-32. DNV Load, Heavy Extrusion, Tire Centered on Plate

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 49/53 37.4 8073 (59.6) 7104 (55.8) HMMWV 50/54 27.3 4930 (34.0) 3966 (27.3) Mk48 LVS 51/55 37.9 7107 (49.0) 6543 (45.1) Chassis Tri GEN 52/56 38.8 6858 (47.3) 5468 (37.7) purpose m353

Table 6-33. DNV Load, Heavy Extrusion, Tire Centered on Stiffener

Vehicle Load Load Plate Bending Stress Plate Bending Stress Case psi Tire @ Midspan Tire @ End psi (N/mm2) psi (N/mm2) LAV 57/61 37.4 5413 (39.9) 4838 (42.4) HMMWV 58/62 27.3 4566 (31.5) 5640 (38.9) Mk48 LVS 59/63 37.9 3037 (20.9) 4186 (28.9) Chasis Tri GEN 60/64 38.8 7071 (48.8) 9265 (63.9) purpose m353

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Figure 6-10. Mk 48 Applied Load and Plate Bending Stresses on Light Extrusion

Figure 6-11. 353 Chassis Applied Load and Plate Bending Stresses on Light Extrusion

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Figure 6-12. Mk 48 Applied Load and Plate Bending Stresses on Heavy Extrusion

Figure 6-13. 353 Chassis Applied Load and Plate Bending Stresses on Heavy Extrusion

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From Table 6-24 it is seen that the ABS and DNV allowable plate stresses are 12,000 psi and 12,530 psi, respectively. In no case are these stresses exceeded by the military vehicle loadout proposed for this project.

A special case was also run using the Mk 48 centered on the plate panel but straddling a transverse floor resulting in a load on two adjacent panels in the longitudinal direction. The analysis was done using the DNV vertical acceleration loads as input. This was of interest due to the possibility of higher Von Mises stresses due to the bi-directional stress field at the end of the plate panel compared to the center of the panel. While the results of this analysis do not define a governing condition it was interesting to note the actual results:

• Plate bending stress Y direction 6671 psi • Plate bending stress X direction 6958 psi • Von Mises stress 7159 psi

From Table 6-32 it is seen that the stresses are greater from that loading scenario, but not much.

6.4.5.1 Discussion of Results of Analysis on ABS and DNV Loads on Heavy and Light Extrusions

As stated above, the deck plate requirement for wheeled vehicles in the ABS rules are formulated on the assumption of simple support boundary conditions, i.e., no resistance to rotation around the perimeter of the plate panel. The M353 satisfies these conditions because the entire footprint lands on a single plate panel when centered on the panel. None of the other footprints fit within a single panel and the portion of the footprint, which overhangs into the adjacent panel will affect the stresses in the most heavily loaded, central panel.

6.4.5.2 Simple Support & Fixed Boundary Conditions

The two classic boundary conditions for much of structural analysis are simple support and fixed support. Simple support boundary conditions allow rotation about the principal bending axis along the side of the plate considered to be simply supported, in many cases, this includes all four edges of the plate panel. The other five degrees of freedom are considered fixed.

With fixed boundary conditions, all six degrees of freedom are fixed implying that there is resistance to rotation about the principal bending axis, it is not free to rotate as in simply supported conditions.

When the load on a plate panel is contained completely within that panel it is assumed to be free to rotate about its edges similar to simple support conditions. The portions of any tire load that overlaps onto adjacent panels effectively restrains the edge of the centrally loaded panel from rotating and helps to affect a fixed condition. This not only changes the stress magnitudes in the various plate panels, it also redistributes the stresses.

In a simply supported plate panel the plate bending stresses are zero along the boundary of the panel and maximum in the center of the panel. In a fixed plate, the bending stresses are maximum at the center of the long edge and half that value at the center of the panel. In

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accordance with Roark and Young, “Formulas for Stress and Strain” [6], the values for plate bending stress for simple and fixed support plate panels are given as follows:

βqb 2 • Simple support Maxσ = σ = at center of plate panel b t 2 β qb 2 • Fixed Support Maxσ = σ = 1 at center of long edge b t 2

β qb 2 σ = σ = 2 at center of plate panel b t 2 where: β, β1 β2 are constants given below, see Table 6-34 q = uniform pressure load over the entire plate panel b = short dimension of the plate panel a = long panel dimension t = panel thickness

Table 6-34. Plate Bending Stress Coefficients From Roark & Young

a/b 1.0 1.2 1.4 1.6 1.8 2.0 ∞ β 0.2874 0.3762 0.4530 0.5172 0.5688 0.6102 0.7500 β1 0.3078 0.3834 0.4356 0.4680 0.4872 0.4974 0.5000 β2 0.1386 0.1794 0.2094 0.2286 0.2406 0.2472 0.2500

It is obvious from these equations that for a given support condition and location the stresses will vary as a function (b/t)2. For the light extrusion (b/t)2 = (200/8.0)2 = 625 while for the heavy extrusion (b/t)2 = (210/9.8)2 = 459.2. Applying these ratios to the stresses in Table 6-26 through Table 6-33 results in fairly close prediction of one stress from an initial stress. For instance starting with Load Case 3, Table 6-26, and trying to predict the stress from Load Case 19, Table 6-28, one would expect a value of 5236 x (459.2/625) = 3847 psi. The actual stress from Load Case 19 is 3672 psi, slightly less than predicted. This is because the Roark equations assume a uniform load over the entire plate, not just a portion of the plate. Regardless, this is fairly good correlation and helps to confirm the accurate behavior of the FEA.

From the equations presented above and their respective values, it is seen that the plate bending stresses at the center of a plate panel should be one-half the value at the side for load on a single panel of fixed plating, i.e., not adjacent plate panels. The original inspiration for developing the FEA was the fact that the footprints that extend over more than one panel would start to induce fixed boundary conditions between the adjacent panels thereby resulting in stress redistributions and reductions compared to the simple support boundary conditions assumed by the ABS design algorithms, shown in Figure 5-15 and Figure 5-16. Table 6-35 and Table 6-36 present summaries of the stresses at the center of the plate panel and the side of the plate panel for the heavy and light extrusion, respectively, for the ABS tire loads in the finite element analysis. The

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effects are the same for the DNV loads and so the actual data is not repeated for them. These tables also include the ratios of the stresses at these two points of interest.

Table 6-35. ABS Plate Bending Stress @ Center & Edge of Light Extrusion (FEA Based)

Vehicle Bending Stress @ Bending Stress @ Ratio Plate Edge Plate Center (Stress @ Center (psi) (psi) /Stress @ Edge) LAV 2291 5941 2.59 HMMWV 2064 3680 1.78 MK 48 3491 5236 1.50 M353 2518 5105 2.03

Table 6-36. ABS Plate Bending Stress @ Center & Edge of Heavy Extrusion (FEA Based)

Vehicle Bending Stress @ Bending Stress @ Ratio Plate Edge Plate Center (Stress @ Center (psi) (psi) /Stress @ Edge) LAV 1956 4171 2.13 HMMWV 1704 2547 1.49 MK 48 2788 3672 1.32 M353 2212 3543 1.60

The results presented in Table 6-35 and Table 6-36 do not agree with the predicted results, i.e., the stresses at the center of the plate panel are not less than the stresses along the edge, in fact, they are greater, indicative of a simple support response.

An interesting relationship is presented in Figure 6-14, which shows the stresses at the center and edge of the plate panel using the heavy extrusion FEA model with the MK 48 tire load and varying the plate thickness from the original 9.8m down to 8mm, 7mm, 6mm and 5mm. This figure shows that as the plate gets lighter the stresses along the edge go up more rapidly than the stresses in the center of the panel. This indicates that as the plate gets lighter it tends to approach the stress distribution anticipated by the β∞ coefficients presented in Table 6-34, i.e., it starts to behave more like a fixed plate panel as the plate gets lighter. This suggests that the (b/t) ratio for the original heavy extrusion is fairly robust and that the tire load that overlaps onto the adjacent panels is not enough to counteract the rotation induced in the plate from the portion of the tire load on the central panel. As the plate thickness is reduced it is more flexible and the overlapping tire load more capable of offsetting the rotations induced within the central panel.

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Plate Bending Stress - vs. Plate Thickness MK48 LVS, ABS, Heavy Extrusion

16000

14000

12000

10000

Plate Center Stress 8000 Plate Edge Stress

Stress [PSI] Stress 6000

4000

2000

0 0.15 0.2 0.25 0.3 0.35 0.4 Plate Thickness [in]

Figure 6-14. Plate Bending Stress vs. Plate Thickness

6.4.6 Structural Optimization Using the ABS Mk 48 Load

A quick comparison is presented using the vehicle deck plate that would be developed using the ABS rules and through the FEA. This is done for the Mk 48 only as a means for developing the comparison. All units of measure in this section are English.

ABS 3-2-3/1.9 presents deck plating requirements for decks subjected to wheel loads. The governing equation is:

βW (1 + 0.5n ) t = xx (inches) σ a where: β = coefficient from 3-2-3/Figure 1 W = static wheel load, pounds nxx = vertical acceleration at location under consideration = 0.24 g’s x 2 per Figure 5-13 for maximum value in the bow. σa = allowable stress from 3-2-3/Table 2 = 0.6σy = 0.6 x 20,000 = 12,000 psi

The Mk 48 tire load is taken from Table 5-22 as 6830 pounds acting over a footprint that is 16” x 27”. The stiffener spacing on the plate panel is 8.27” (210 mm). This implies that, when the tire is centered on a given plate panel only (8.27/16) x 6830 = 3530 pounds is on the centrally loaded panel. This is the value that will be taken for W. β = 0.57 is determined from the panel dimension of 8.27” x 47.24” (210 mm x 1200 mm) and the tire footprint of 16” x 27”. Using

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these values results in the following required deck plate thicknesses for the Mk 48 located in the bow and at midship, respectively, within the ship:

0.57()3530 ()1+ 0.5 ()0.48 t = = 0.456 inches = 11.58 mm for bow location of Mk 48. 12,000

0.57()3530 ()1+ 0.5 ()0.24 t = = 0.433 inches = 11.01 mm for midship location of Mk 48. 12,000

There is not a significant difference for the required plate thickness by moving the vehicle from the bow to the midship area of the ship.

From Table 6-28, Case 19, it is seen that the stress in the heavy extrusion with a thickness of 0.386 inches (9.8 mm) is 3672 psi, significantly below the ABS allowable stress of 12,000 psi. To investigate the reduction possible in the deck plate through FEA the model was run with the ABS Mk 48 loads using 5 mm and 6 mm plate. The results of this data are plotted in Figure 6-14 without any specific values for the plate thicknesses. For 6 mm plate the maximum stress is 9410 psi while the 5mm plate experiences a maximum stress of 13,961 psi, the latter exceeding the allowable stress of 12,000 psi. This suggests that, in comparison to the ABS plate design algorithm, which would require 11mm/12mm deck plate, the FEA would allow the vehicle deck to be designed using 6mm plate. Minimum thickness criteria for ruggedness would still have to be checked but this is a good indication of the optimization that could be attained using FEA in this instance. This is particularly noteworthy for new design consideration.

6.4.7 Verification of the Finite Element Results

One model, analyzed with two sets of boundary conditions, was used to verify that the finite element models being used for these analyses were correctly developed and their results correctly interpreted. The analyses are:

• Plate panel, simply supported, (pinned) around its entire perimeter and subjected to a 20 psi uniform load over the entire panel and, • Plate panel, fixed around its entire perimeter and subjected to the same 20 psi load.

The plate panel was extracted from the model used for the analyses of the heavy extrusion and has the following properties:

s = 8.25”, l = 47.25” t = 0.3858”, E = 9.9 x 106 psi

The results of the FEA verification runs were compared to the theoretical predictions using the equations presented by Roark & Young, “Formulas for Stress and Strain” [6]. The results of the comparison are provided in Table 6-37. All comparisons are acceptable.

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Table 6-37. FEA Results vs. Roark Predictions

Case Finite Element Value Roark Stress % Difference Pinned – Stress at Center 6844 psi 6859 psi -0.22% Fixed Support - Stress @ Center 2290 psi 2286 psi 0.17% Fixed Support - Stress @ Edge 4485 psi 4572 psi -1.90% Pinned - Deflection @ Center 0.0228” 0.0231” -1.30% Fixed Support, Deflection @ 0.00468” 0.00463” 1.08% Center

6.5 DRAWINGS FOR STRUCTURAL MODIFICATIONS

The ABS and DNV required structural modifications are provided on marked-up drawings in Figure 6-15 through Figure 6-20. A brief summary of the changes is included on the appropriate figure. The modifications shown on these drawings are the same as those used for the weight increase calculations presented in Table 6-17 and Table 6-23.

These drawings show the structural modifications required to meet the slam load requirements for the conversion. There are no modifications required for either global hull girder loads or vehicle deck operation with the MEU loadout defined for this project. None of these drawings are intended to address the local requirements for installation of the tiedowns, details for which are provided later.

The ABS structural modifications are shown in Figure 6-15 through Figure 6-18 and the DNV modifications are shown in Figure 6-19 and Figure 6-20. All modifications are indicated by the red text that has been added to these drawings. There is no separate drawing provided for the side shell flange doublers that need to be added for DNV since they are effectively the same as those required for ABS. These modifications are shown in Figure 6-15 and Figure 6-16.

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ABS Mods Outbd – Main Vehicle Deck to upper chine in the Lower Hull, FWD & AFT

ABS Mods Inbd – Upper chine of Lower Hull to the lower knuckle in the Haunch, FWD & AFT

Approximate location of mods are shown below

(ABS MODIFICATIONS)

CONFIDENTIAL INFORMATION

Figure 6-15. ABS Structural Modifications – Forward Portion of Side Shell

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(ABS MODIFICATIONS)

CONFIDENTIAL INFORMATION

Figure 6-16. ABS Structural Modifications – Aft Portion of Side Shell

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CONFIDENTIAL INFORMATION (ABS MODIFICATIONS)

Figure 6-17 ABS Structural Modifications – Forward Portion of Bottom Hull

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CONFIDENTIAL INFORMATION

(ABS MODIFICATIONS)

Figure 6-18 ABS Structural Modifications – Aft Portion of Bottom Hull

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(DNV MODIFICATIONS) DNV Mods are limited to the Lower Hull and they do not extend above the upper chines, either inboard or outboard.

Approximate location of mods is shown below

CONFIDENTIAL INFORMATION

Figure 6-19. DNV Structural Modifications – Forward Portion of Bottom Hull

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(DNV MODIFICATIONS)

CONFIDENTIAL INFORMATION

Figure 6-20. DNV Structural Modifications – Aft Portion of Bottom Hull

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6.6 VEHICLE DECK TIE DOWNS

A primary concern that was soon dispelled involved the use of steel tiedowns in aluminum deck structure. Previous experience suggested that tiedown fittings were only available in steel and typical practice would discourage the use of steel fittings in an aluminum deck. It also did not seem likely that aluminum fittings for this function would be available due to the rugged nature of the fittings operation – not an operation thought to be well suited to a relatively malleable material like aluminum.

Inquiry to various fittings manufacturers, Peck & Hale and Pacific Marine and Industrial, quickly revealed that there is a common application for vehicle tiedown fittings in aluminum decks. Indeed, the fittings are steel and isolated from the aluminum deck structure with gaskets to prevent galvanic action between the dissimilar metals. A sealant is applied around the perimeter of the tiedown after it is bolted into place to provide a watertight boundary. This is typical practice and an application of a typical cloverleaf fitting on HSV-X1 is shown below in Figure 6-21, which also include one of the original tiedown tubes included on the HSV-X1. The tiedown tubes have very limited capacity, approximately 0.8 short tons and are not usually included in tiedown applications for military vehicles and will not be considered effective or included on the PacifiCat conversion.

Figure 6-21. Typical Cloverleaf Tiedown Shown on HSV-X1 (With Original Tiedown Tube)

6.6.1 Arrangement of Vehicle Tiedowns

A typical vehicle deck on a military vessel includes a grid of tiedowns on 4-foot centers. There are two reasonable possibilities for vehicle deck tiedowns on the PacifiCat:

1. Provide a general grid of tiedowns on 4-foot centers similar to that provided on other vehicle decks. 2. Provide a tiedown arrangement that specifically reflects the vehicle arrangement shown in Figure 6-5.

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Providing the specific tiedown arrangement to reflect Figure 6-5 has the advantage of minimizing the cost impact for converting the vessel. However, it may also become too restrictive for overall use of the vessel. Regardless, the requirement for the number of tiedown fittings to suit the conversion is fairly extensive and providing an arrangement for the conversion will still satisfy the academic nature of this project. Typical structural details are shown below, Figure 6-23, for the converted deck structure in way of the tiedowns.

The spacing of the transverse floors below the Main Vehicle Deck is 1.2 meters throughout the deck, which is approximately 47.2 inches, i.e., 4 feet, the same spacing typically used for a tiedown arrangement. This lends itself very nicely to arranging the tiedowns in a manner that is coordinated with the floors and consistent with typical tiedown arrangements.

Two typical tiedowns with capacities required for this project are shown in Figure 6-22. These tiedowns mount into the deck similar to most US Navy vehicle decks, i.e., they are flush mounted tiedowns. Protruding tiedowns will have a bolting flange that allows bolting to the vehicle deck structure. The typical detail proposed for the PacifiCat is shown in Figure 6-23.

Breaking Load: 160kN Breaking Load: 315Kn (36,000 lb) (70,800 lb)

Figure 6-22. Typical Flush Cloverleaf Tiedown Fittings

The following information, Table 6-38, for the number and size/capacity of tie down fittings required for each vehicle is taken from Marine Lifting and Lashing Handbook, MTMCTEA REF 97-55-22, Table 4-1 [3] for “Other Ships”, referring to all ships other than FSS and large,

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medium speed RO/RO ships, which have reduced lashing requirements due to the large sizes of these ships and their relatively low motions in extreme seas.

Table 6-38. Vehicle Lashing Requirements, US Marines

Vehicle Weight Lashing Strength Total Number of Required (Lbs) (Lbs) Lashings Up to 5260 5000 4 Up to 10,530 10,000 4 Up to 14,850 14,100 4 Up to 17,900 17,000 4 Up to 36,860 35,000 4 Up to 73,720 70,000 4 Up to 147,450 70,000 8

Based on the vehicle loadout proposed for this project and their respective weights, Table 6-39 summarizes the tiedowns that are nominally required for the military loadout based on vehicle weight.

As seen in Table 6-39, the conversion only includes one vehicle that exceeds 36,860 pounds and that is the 7-T M927, Extended Bed Truck, with a weight of 37,000 pounds. The loadout only includes one of these trucks.

Table 6-39. Tiedown Requirements for the Conversion

Vehicle Weight Number of Total Number of (Lbs) Vehicles in Weight Tiedowns Required at Range Given Strength Up to 5260 30 120 @ 5000 lb 5260 to 10,530 31 124 @ 10,000 lb 10,530 to 14,850 1 4 @14,100 lb 14,850 to 17,900 2 8 @ 17,000 lb 17,900 to 36,860 22 88 @ 35,000 lb 36,860 to 73,720 1 4 @ 70,000 lb 73,720 to 147,450 0 0 @ 70,000 Σ = 348 tiedowns

As shown in Table 6-39, a total of 348 tiedowns are required to satisfy the nominal requirements for this conversion study. Practical considerations prohibit using the entire array of tiedowns reflected in the table. All of the vehicles heavier than 17,900 pounds are arranged on the heavy extrusion, Figure 6-5. The TRLR, Mk 14 weighs 16,000 pounds and accounts for the two vehicles in the weight category of 14,850 to 17,900 pounds. As such, it is easy to select two tiedown sizes to accommodate the entire conversion effort. 70,000 pound tiedowns will be used for all the vehicles on the heavy extrusion and 17,000 pound tiedowns will be used for all other

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vehicles. This simplifies installation and increases flexibility for arranging vehicles within the deck.

The cost estimate for the task will be based on the following number of tiedowns:

• Number of 17,000 pound tiedowns = 1.25 x (120 + 124 + 4 + 8) = 320

• Number of 70,000 pound tiedowns = 1.25 x (88 + 4) = 115

The tiedowns are increased by 25% to allow for additional tiedown installations beyond the minimum for increased loading flexibility. It also provides a nominal margin on a portion of the conversion cost that is relatively inexpensive.

6.6.2 Installation of Vehicle Tiedowns

The vehicle tiedowns will be installed in the PacifiCat in a manner similar to the HSV-X1, i.e., they will be bolted into the deck structure, not welded into the deck plate and stiffening as is typical with many US Navy vehicle decks. As a result, they will be raised tiedowns, which protrude above the deck surface, not flush tiedowns typical of a deck fabricated specifically for transport of military vehicles. A typical raised tiedown is shown on the HSV-X1 in Figure 6-21. A sketch showing the basic installation envisioned for the PacifiCat is provided in Figure 6-23. The tiedowns will be centered on the transverse floors and the longitudinal stiffeners associated with the extrusions. This will allow each tiedown to be aligned with the deck stiffener upon which it is centered and not interfere with the stiffeners to either side, i.e., it will keep the bolts clear of the longitudinal stiffening. The floor and the stiffener provide good local support to help resist the bolt forces developed in the tiedown. The portion of the transverse floor that protrudes above the vehicle deck will be ground smooth with the surrounding deck so that there is a flush bolting surface. The grinding and installation process will be accomplished with smooth transitions in way of all tiedown installations to ensure there are no stress raisers causing early cracking problems or stress concentrations. The local strength and tightness of the extrusion in way of the area ground smooth will be inspected. If necessary, additional welding in way of the ground area will be performed to ensure that the required strength and tightness in way of this connection is maintained.

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Portion of transverse web protruding above deck, to be ground smooth

Longitudinal stiffener

Figure 6-23. Detail of Vehicle Tiedown Installation Proposed for PacifiCat

The cost estimates for the conversion of these vessels will assume that they are bolted through the Main Vehicle Deck plate using four bolts capable of withstanding the tiedown loads, as calculated below.

6.6.3 Bolting Requirements for the Tiedowns

The bolts used to secure the tiedowns to the deck structure need to be able to withstand the full load exerted by the lashing. The force in the lashing will be resisted by a combination of shear and tension in the tiedown bolts. The deck plate also needs to be checked to ensure that the bolts will not cause pull-through failure as the tensile load they support bears against the deck plate.

6.6.3.1 Size of Tiedown Bolts

These calculations assume that all bolts are Grade 5 (ASTM A 325). For bolts up to ¾” these can sustain a proof load of 85,000 psi with a tensile strength of 120,000 psi. The allowable tensile stress in the bolt shall be taken as 60% of the proof load = 51,000 psi and the allowable shear stress shall be taken as 60% of the yield in shear = 0.6 x (85,000/√3) = 29,500 psi.

Neither ABS nor DNV has any criteria immediately available for bolt sizing. This report will use the procedures typical for US Navy bolt calculations for foundation design where the tensile and shear stresses are determined as:

2 2 0.5P  0.5P   V      Ft = +   +   At  At   As 

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and

2 2  0.5P   V      Fv =   +    At   As  where: Ft = tensile stress in the bolt Fv = shear stress in the bolt P = tensile load V = shear load At = bolt tensile area at threads when checking tension only and at shank when combining with shear Av = bolt shear area through shank

The calculations performed for the bolts are simplified and assume that the load in the bolts is the result of a load in the lashing equal to the capacity of the tiedown acting at an angle of 450 to the deck.

With these assumptions, the 70,000 pound tiedowns can be supported on the heavy extrusion using four, 5/8” Grade 5 bolts. The bolts will develop axial and shear stresses of Ft = 38,051 psi and Fv = 24,363 psi, respectively. This study assumes that all tiedowns with a rating of less than 70,000 pounds will use four, 1/2” bolts, which when supporting a 17,000 pound tiedown, develop their maximum stresses of Ft = 29,211 psi and Fv = 18,630 psi. Using different bolt sizes for each different tiedown rating would complicate fabrication and increase the likelihood of installing the incorrect bolt/tiedown combination. This is justified because the cost of using the 1/2” bolts for all smaller installations will be negligible in comparison to the other costs associated with the conversion.

The total number of bolts purchased for the conversion is shown in Table 6-40.

Table 6-40. Grade 5 Bolts Required for Tiedowns

Total Number of Number and Size of Tiedowns Required at Grade 5 Bolts Given Strength 120 @ 5000 lb 480 – 1/2” 124 @ 10,000 lb 496 – 1/2” 4 @14,100 lb 16 – 1/2” 8 @ 17,000 lb 32 – 1/2” 88 @ 35,000 lb 352 – 5/8” 4 @ 70,000 lb 16 – 5/8” 0 @ 70,000 0 Σ = 348 tiedowns Σ = 1024 – 1/2” bolts Σ = 384 – 5/8” bolts

The cost estimate for the task will be based on the following number of bolts:

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• Number of 1/2” bolts = 1.25 x (480 + 496 + 16 + 32) = 1280

• Number of 5/8” bolts = 1.25 x (352 + 16) = 460

The bolts are increased by 25% to allow for the same margins as the tiedown installations cited above.

6.6.3.2 Pull-Through Stresses on Vehicle Deck Plate

The pull-through stress is calculated using the following equation:

P σ = pull−through 1.5πdt where: d = nominal bolt diameter t = deck plate thickness

The allowable shear stress for the deck plate shall be assumed to be 40% of the welded yield strength for ABS and taken as 90f1 for DNV from DNV 3-3-5/C200. Neither regulatory body has specific criteria for this loading but such allowable stresses are consistent with typical practice for similar designs.

The welded yield strength of the 6061-T6 extrusion is 20,000 psi resulting in an ABS Allowable stress of 8000 psi.

2 For 6061-T6 DNV defines f1 = 0.48 resulting in an allowable shear stress of 43.2 N/mm = 6266 psi.

As shown in Figure 6-5, all of the vehicles using the 70,000 pound tiedown fittings have been located within the heavy extrusion of the Main Vehicle Deck. For the 70,000 pound tiedown with 5/8” bolts in the heavy extrusion the pull-through stress is 5442 psi and the pull-through stress of the 1/2” bolts supporting the 17,000 pound tiedown in the light extrusion is 4049 psi. Both stresses are acceptable with the criteria defined above.

No calculations are performed for the shear reaction of the bolts against the deck plate, what would typically be referred to as “Tearout Failure” of a bolt ripping through the flange of a foundation installation. These calculations are typically required to ensure that there is enough shear area in the bolting flange to resist the shear force developed in the bolt. In the current installation the shear force developed in the bolts will cause them to bear against the vehicle deck plating, which is regarded as having a large amount of deck plate effective in resisting this force.

6.6.4 Vehicle Lashing Requirements

The lashing requirements are only addressed to determine an approximate weight impact to account for this component of the loadout. Reference [3], USMC Lifting and Lashing Handbook, does not contain any information regarding the weight of the lashing hardware. To estimate the weights for this report the vehicles included in the loadout are grouped by weight in accordance with Table 4-1, from reference [3]. This grouping is presented below in Table 6-41.

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The following unit weights are used to develop the lashing weight estimates provided below. Each lashing consists of:

• 1 Level/ratchet load binder @ 7.75 pounds

• 10 feet of chain @ 0.63lb/ft for 1/4” chain; 1.41 lb/ft for 3/8” chain & 2.50 lb/ft for 1/2” chain

• 2 hooks @ 0.85lb/1/4” hook; 1.38lb/3/8” hook & 3.00 lb/1/2” hook

As shown in Table 6-41, each vehicle requires four lashings. The lashing components described above correspond to the “Light”, “Medium” and “Heavy” lashings typically referred to in this application. The Heavy lashings are used for much larger/heavier vehicles than included in the current loadout, i.e., M1A1 tanks which weigh in at approximately 130,000 pounds per tank. These calculations assume that the two lightest categories in Table 6-41 are secured by “Light” lashings, i.e., 1/4” and the three heaviest categories by “Medium”, 3/8”, lashing components. As such the unit weight of each lashing is determined as:

• 1/4” lashing = 7.75 + 10(0.63) + 2(0.85) = 15.75 pounds per lashing

• 3/8” lashing = 7.75 + 10(1.41) + 2(1.38) = 24.61 pounds per lashing

Table 6-41 Weight of Vehicle Lashing Hardware

Vehicle Required Total Number Number of Assumed Total Weight Lashing of Required Vehicles in Weight per Lashing Strength Lashings Loadout Vehicle Weight Lashing Set (Lb) (Lb) Up to 8930 lb 5000 lb 4 57 15.75 x 4 = 63.0 3591.0

Up to 17,860 10,000 lb 4 7 63.0 441.0 lb

Up to 25,180 14,100 lb 4 5 24.61 x 4 = 98.44 492.2 lb

Up to 30,360 17,000 lb 4 8 98.44 787.5

Up to 62,510 35,000 lb 4 12 98.44 1181.3

Σ 6493.0

The total lashing weight shown in Table 6-41 of 6493 pounds is equal to 3.25 short tons = 2.95 metric tonnes.

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6.7 IMPACT ON RANGE, SPEED AND ENDURANCE FROM CONVERSION

Earlier work done with the PacifiCat was used to develop the curves for range and speed. Figure 6-24 shows some of the original predictions and test results for the speed – power performance of the ship. The original design has an installed power of 26,000 kW and a displacement of 1885 metric tonnes. This includes a deadweight tonnage of 518 metric tonnes with 66 metric tonnes of fuel oil.

30000

25000

20000

15000

Power, KW (all engines) Power, 10000 Model Test Predictions at 1735 t

5000 Trials Results at 1735 t "Trials" Predictions at 1891 t 0 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Speed, Knots

Figure 6-24. Estimate of PacifiCat Speed – Power

Figure 6-25 shows the estimates on range based on speed and fuel load developed for this task. It is expected that the fuel load could be increased by judicious removal of structure and outfitting that would no longer be required on the converted vessel. The original design included accommodations for 1000 crew and passenger. The converted vessel would have a nominal crew with zero passengers, although overnight berthing/accommodations and a full galley would also be required on the converted vessel. A complete study of this aspect of the conversion would have to be made to determine the exact additions and removals that could be incorporated into the converted vessel. The varying fuel loads shown in Figure 6-25 refers to the total weight of fuel carried on-board to achieve the speed/range profiles in the figure.

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700 639.2 605.0 580.2 568.1 562.3 600 549.8 537.8 541.8 537.5 515.7 497.1 499.8 488.7 481.6 470.6 477.8 500 451.3 437.3 426.1 427.6 421.4 418.1 403.4 386.8 374.8 400 366.5 361.2 358.3 `

300

Range [nautical miles] [nautical Range 60T Fuel Load [nautical miles] 200 70T Fuel Load [nautical miles] 80T Fuel Load [nautical miles] 90T Fuel Load [nautical miles] 100

0 31 32 33 34 35 36 37 38 39 Speed [knots]

Figure 6-25. PacifiCat Range vs. Speed for Varying Fuel Loads

Figure 6-26 provides an estimate of the fuel loads required for a 4000 nautical mile transit at various speeds, i.e., it is necessary to carry nearly 500 metric tonnes of fuel to transit 4000 nautical miles at 37 knots. In accordance with the brochure information provided in Section 3.5.1 of this report, the baseline fuel load is 66 metric tonnes. The vessel is not configured to carry 500 tonnes of fuel and it would be necessary to add tankage, i.e., fuel trailers, to achieve this loadout, which would also reduce all other payload capacity to zero. Realistic use of the PacifiCat as a sealift vessel would probably be more beneficial in a theater support or sea-basing operation. The modification requirements and fuel load constraints on an R4 are probably too great to allow for its efficient use in a trans-oceanic mode. For local, in-theater service, the PacifiCat would make for a good vessel.

510

500

490

480

470

460

450 Fuel Weight [mt] Weight Fuel

440

430

420

410 31 32 33 34 35 36 37 38 39 Speed [knots]

Figure 6-26. Fuel Load vs. Speed – 4000 Nautical Mile Transit

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6.8 FATIGUE ANALYSIS

The Statement of Work for this project does not require any fatigue analysis. The following discussion is presented for general consideration.

The requirements for fatigue analysis would have to be specially developed for any conversion. While fatigue is important for any design, and for high speed aluminum craft, in particular, the conversion aspect requires augmenting the considerations that would typically be addressed for a new design to those that would be more specifically developed for the actual vessel being converted.

Considerations would include the age of the vessel being converted and its own fatigue history or fatigue related problems and the anticipated loading profile/histogram for the converted vessel. The loading histogram developed for any ship converted into the mission required for this project would consist of the following components:

1. Loading history prior to conversion, i.e., commercial operation, 2. Loading history subsequent to conversion, i.e., military operation, 3. Loading history subsequent to military mission, i.e., return to commercial operation.

The third portion of this loading history may be unknown at the time of conversion and it may be assumed that the balance of the service life of the vessel will be spent performing the military mission. This would probably lead to a conservative assessment of the loading histogram since it is expected that the loading spectra associated with the military mission would be more severe than those experienced during commercial operation.

The loading history prior to the conversion would not include any loads due to the open ocean environment. The loading history subsequent to the conversion would include open ocean loads and a realistic assessment of the total exposure time in the open ocean would have to be determined in order to assess the load magnitudes and cycles, i.e., loading spectra, for the global hull girder and secondary slam loads. It is not expected that the converted vessel would spend significant time in the open ocean, only be required to transit to get in theatre.

After assessing the loads required for the conversion by both ABS and DNV and also developing the local loads required for the vehicle deck, it can be seen that the loading histogram for the ship would be increased compared to any originally defined histogram however, the load cycles associated with this new mission of the vessel would also have to be considered. As discussed in Section 2 of this report, it will take between 20 and 30 sorties to complete the delivery of a single MEU. The load cycles associated with this would have to be determined along with the actual exposure time anticipated in the open-ocean environment to accurately determine the new loading profile for primary hull girder and slamming loads. These considerations would all have to be quantified as input to the load histogram.

Regarding ABS and DNV criteria for fatigue analyses in their respective high speed rules:

• The ABS HSNC rules do not contain any specific requirements for fatigue design. Development of any fatigue analysis would be as required for the conversion

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specification although the requirements for any fatigue analysis may be tempered, or more strongly reinforced, depending on the fatigue history/performance of details prior to the conversion.

• The DNV HSLC & NSC covers fatigue analysis through their Direct Calculation Methods in Part 3, Chapter 9. Section 6 addresses Fatigue Analysis and presents only brief discussion regarding the procedures to be followed for the analysis. This includes defining a minimum service life not less than 20 years and using the Palmgren-Miner linear cumulative damage assessment to define acceptance.

6.9 CONCLUSIONS REGARDING STRUCTURAL MODIFICATIONS

The structural modifications required for the PacifiCat’s, originally designed for DNV R4 Service Area Restrictions, are not as severe as originally anticipated. The relatively deep hull girder helps to limit the modifications necessary to satisfy global requirements and the relatively tight stiffener spacing yields a fairly robust structure for resisting the local slam loads as well as the tire loads on the vehicle deck extrusions.

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7.0 STRUCTURAL MODIFICATION COST ESTIMATES

This section of the report presents the cost estimates for the structural conversions required to incorporate the ABS and DNV structural modifications defined above. Each of the estimates also includes the cost for outfitting the Main Vehicle Deck with the tiedown sockets and supporting structure identified above. There are no costs included for the lashing equipment that would be required to actually secure the vehicles to the fittings.

The cost estimate information provided below is copied from a spreadsheet used to assemble and simplify all information associated with the estimate.

7.1 CONCLUSION

As detailed in the cost estimates shown below, the cost for the ABS modifications are less than the DNV modifications. The total costs including Outfit and Yard Services are:

• ABS $1,136,531 • DNV $1,927,699

The breakdown of the cost estimates is provided below.

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APPROACH

This worksheet presents a summary of the conversion cost estimate for an Aluminum Car Ferry to support the efforts for this task.

The estimate was developed using material take-offs as calculated in Section 6. Costs for the plate and shapes were based on normalized market costs for equivalent grade materials, as available from public resources. Labor hours were based on JJMA experience with marine aluminum-based conversion work; cross-checked where practicable with industry and cost analyst data for like activities and motions. Labor costs were based on commercially oriented, 2nd tier yards, and were set at $45/Hour without fee.

CALCULATIONS

Bottom Plate

Removal of the bottom plate was estimated using available algorithms for cutting of existing plate; removal of identified stiffening for replacement with more robust structure, preparation of the remaining stiffening to support welding, and installation of the new plate. It should be noted that the removal and installation of the bottom stiffening is documented in the following tables.

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All plate is 5083 or equal per the technical report. This plate is estimated at a nominal $1.25/pound ($2.75/kilogram) based on July 2004 spot market rates for aluminum; and modified to reflect the additional costs for preparing this particular alloy. A wastage factor of 15%, unless noted otherwise, was applied to the weight of the plate to account for losses due to nesting. This factor is based on experience with nesting of similar simple shapes as provided by representative 2nd tier yards.

All shapes are also from 5083 or equal per the technical report. The costs for these shapes was estimated at 20% over the regular plate cost identified above. This estimating technique was used in place of spot market quotes for the identified shapes as costs for these shapes were not readily available. Other costs for shapes in this size and material range were available, and that information was used to calculate the cost growth associated with the shapes. The 20% is what resulted.

All welding was assumed to be continuous heliarc or similar welding. Materials including gases and welding materials are estimated and accounted for in this element.

To clarify the plate and stiffener removal process:

Under the heading Remove bottom plate

Perimeter cutting of plate – cut around the entire perimeter of the plate panel being removed.

Stiffener cutting – cut thru the welds that connect the stiffening to the plate so the plate comes off and the stiffening remains in place.

Under the heading Remove Bottom Structure

Stiffener cuts – cuts are now made where the transverse and longitudinal members need to be separated from the ship to complete the removal.

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SUMMARY

The following tables summarize the two cost estimates, one for ABS, the second for the DNV. Cost calculations were based on the material take-offs specific to the rules being applied. Tie down costs are identical for both studies as the deck arrangement and quantities were the same. Outfitting items are based on material take-offs, predominately painting. Yard services were based on a predicted timeline, which was identical for both studies.

A 20% factor was applied to the direct work to account for on-site engineering and program management. This is representative of costs for similar programs.

Fee was applied at 10%, representative of a normal 2nd tier repair-yard fee structure.

ABS DNV ACTION Cost, FY05 Cost, FY05 Remove Plate $ 8,219 $ 14,389 Remove Stiffening $ 12,220 $ 30,850 Install Plate $ 37,855 $ 120,805 Install Flange Doublers $ 160,378 $ 160,683 Install Stiffening $ 71,662 $ 311,182 Install Tie Downs $ 146,369 $ 146,369 Outfit Services $ 76,769 $ 328,564 Yard Services $ 347,536 $ 347,536 Sub-Total $ 861,008 $1,460,378 Engineering/Supervision @ 20% $ 172,202 $ 292,076 Sub-Total $1,033,210 $1,752,454 Fee @ 10% $ 103,321 $ 175,245 TOTAL $1,136,531 $1,927,699

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ABS SLAM LOAD - OPEN OCEAN, UNRESTRICTED Remove bottom plate 6,265 kg Perimeter Cutting -- equivalent of 2.25m-6.10m sheets each weighs an average of 525kg. 12.00 Equiv Sheets

Perimeter cutting takes an average of 15 cm/minute with a 2-person team 3.71 Hours/Sheet

Stiffener cutting -- equivalent of 9 stiffener runs per panel Each assumed to have intermittent welds [50%], 10.13 meters of weld

Cutting is equivalent to perimeter cutting 2.25 Hours/Sheet

Net Labor Effort 72 Hours

Item Units Rate Cost Labor Effort 72 Hrs $ 45 $ 3,219 Gases 1 Lot $ 5,000 $ 5,000 Net Cost, Bottom Panels Removal $ 8,219

Remove Bottom Structure 3,284 kg * Assumes perimeter cuts only required to break structure free of the vessel. At 9 members per panel, and 2 edges per member, we see 18 cuts per panel. 18.00 Cuts/Panel

At the identified # of panels 12.00 Equiv Sheets

Total # of cuts 216.00 Cuts

Using available references, identify 30 minutes per cut to prepare, execute, and take-down. Assumes a 2 person team

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Net Labor Effort 216 Hours

Item Units Rate Cost Labor Effort 216 Hrs $ 45 $ 9,720 Gases 0.5 Lot $ 5,000 $ 2,500 Net Cost, Bottom Stiffeners Removal $ 12,220

ABS SLAM LOAD - OPEN OCEAN, UNRESTRICTED Add New Bottom Structure 7,048 kg Plate preparation, nesting, cutting and edge preparation * Assume 8 hours to prepare nesting, check CNC data, and position the plate * Cut Plate, prepare edges -- 4 hours per plate/panel * Weld plate in place; assumes backing structure was positioned prior Welding set at 6 meters/hour for a 2-person team ($45/hr-person * 2 people/6M-Hr). * Assumes a 15% nesting factor. * Stiffening welds-determined stiffener perimeter based on shape [AVG] 0.628 Determined # of welds based on diagram as approximately 70 Total linear meters of stiffening welds -- edges 43.96 Total linear meters of stiffening welds -- runs 1360

# of Units Unit Cost Total Cost Plate Cost 8,105 kg $ 2.75 $ 22,289 Plasma Cutting set-up Labor [$45/Hr] Assumes 12.00 panels 14 panels $ 540.00 $ 7,560 Weld Plate In Place [2 man team; 6m/Hour] Perimeter Weld 200 meters $ 15.00 $ 3,006

assumes continuous welds

Gases and materials 1.00 lot $ 5,000.00 $ 5,000

Net Material Cost, Bottom Panels $ 37,855

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Add New Flange Doublers, cut from pl 1,590 kg Plate preparation, nesting, cutting and edge preparation * Assume 8 hours to prepare nesting, check CNC data, and position the plate * Cut Plate, prepare edges -- 4 hours per plate/panel * Multi-head cutting tool cuts flange doubler strips- 8 hrs per panel Field install all doublers - provide gasses and ventilation on ship * Assumes a 15% nesting factor. * Flange doubler welds based on 360 pcs @ 32mm and 2790 pcs @ 25 mm 3150 Each pc is 1.2m, intercostal between frames, continuous weld both edges 2.4 Total linear meters of flange doubler welds -- edges 7560 Two pcs per hour welded in place in ship includes clamping time (2 man team @ $45/hr-person)

# of Units Unit Cost Total Cost Plate Cost - to cut flange doubler strips 1,829 kg $ 2.75 $ 5,028 Plasma Cutting set-up Labor [$45/Hr] Assumes 4.00 panels 4 panels $ 900.00 $ 3,600 Weld flange doubler in place on ship [2 man team; 2pcs/Hour] Perimeter Weld 3,150 pieces $ 45.00 $ 141,750

assumes continuous welds

Gases and materials 2.00 lot $ 5,000.00 $ 10,000

Net Material Cost, Bottom Panels $ 160,378

Add New Bottom Stiffening 3,284 kg Shape preparation, nesting, cutting and edge preparation * Assume 2 hours to prepare nesting, check CNC data, and position the shape * Cut Plate, prepare edges -- 1 hours per shape (15% nesting factor) * Weld plate in place; assumes backing structure was positioned prior Welding set at 6 meters/hour for a 2-person team.

# of Units Unit Cost Total Cost Shape Cost 3,777 kg $ 3.30 $ 12,463

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Plasma Cutting Assumes 108.00 Shapes 108 shapes $ 135.00 $ 14,580 Weld Plate In Place Line Weld 2,720 meters $ 15.00 $ 40,800 Edge Welds 88 meters $ 15.00 $ 1,319 assumes continuous welds

Gases and materials 0.50 lot $ 5,000.00 $ 2,500

Net Material Cost, Bottom Stiffening $ 71,662

DNV SLAM LOAD - OPEN OCEAN, UNRESTRICTED Remove bottom plate 18,230 kg Perimeter Cutting -- equivalent of 2.25m-6.10m sheets each weighs an average of 525kg. 35.00 Equiv Sheets

Perimeter cutting takes an average of 15 cm/minute with a 2-person team 3.71 Hours/Sheet

Stiffener cutting -- equivalent of 9 stiffener runs per panel Each assumed to have intermittent welds [50%], 10.13 meters of weld

Cutting is equivalent to perimeter cutting 2.25 Hours/Sheet

Net Labor Effort 209 Hours

Item Units Rate Cost Labor Effort 209 Hrs $ 45 $ 9,389 Gases 1 Lot $ 5,000 $ 5,000 Net Cost, Bottom Panels Removal $ 14,389

Remove Bottom Structure 16,096 kg * Assumes perimeter cuts only required to break structure free of the vessel. At 9 members per panel, 190

and 2 edges per member, we see 18 cuts per panel. 18 Cuts/Panel

At the identified # of panels 35 Equiv Sheets

Total # of cuts 630 Cuts

Using available references, identify 30 minutes per cut for the "baseline" used on the ABS analysis; assumes a 2 person team. Same assumption used for ABS

Times 630 cuts = 630 hrs

Net Labor Effort 630 Hours

Item Units Rate Cost Labor Effort 630 Hrs $ 45 $ 28,350 Gases 0.5 Lot $ 5,000 $ 2,500 Net Cost, Bottom Stiffeners Removal $ 30,850

DNV SLAM LOAD - OPEN OCEAN, UNRESTRICTED Add New Bottom Structure 27,016 kg Plate preparation, nesting, cutting and edge preparation * Assume 8 hours to prepare nesting, check CNC data, and position the plate * Cut Plate, prepare edges -- 4 hours per plate/panel * Weld plate in place; assumes backing structure was positioned prior Welding set at 6 meters/hour for a 2-person team ($45/hr-person * 2 people/3M-Hr). * Assumes a 15% nesting factor. * Stiffening welds -- determined perimeter of stiffener based on shape 1.2 Determined # of welds based on diagram as approximately 200 Total linear meters of stiffening welds -- edges 240 Total linear meters of stiffening welds -- runs 4065.6

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# of Units Unit Cost Total Cost Plate Cost 31,068 kg $ 2.75 $ 85,438 Plasma Cutting set-up Labor [$45/Hr] Assumes 35.00 panels 40 panels $ 540 $ 21,600 Weld Plate In Place [2 man team; 10m/Hour] Perimeter Weld 585 meters $ 15 $ 8,768

assumes continuous welds

Gases and materials 1.00 lot $ 5,000 $ 5,000

Net Material Cost, Bottom Panels $ 120,805

Add New Flange Doublers, cut from pl 1,544 kg Plate preparation, nesting, cutting and edge preparation * Assume 8 hours to prepare nesting, check CNC data, and position the plate * Cut Plate, prepare edges -- 4 hours per plate/panel * Multi-head cutting tool cuts flange doubler strips- 8 hrs per panel Field install all doublers - provide gasses and ventilation on ship * Assumes a 15% nesting factor. * Flange doubler welds based on 3160 pcs @ 25mm 3160 Each pc is 1.2m, intercostal between frames, continuous weld both edges 2.4 Total linear meters of flange doubler welds -- edges 7584 Two pcs per hour welded in place in ship includes clamping time (2 man team @ $45/hr-person)

# of Units Unit Cost Total Cost Plate Cost - to cut flange doubler strips 1,776 kg $ 2.75 $ 4,883 Plasma Cutting set-up Labor [$45/Hr] Assumes 4.00 panels 4 panels $ 900.00 $ 3,600 Weld flange doubler in place on ship [2 man team; 2pcs/Hour] Perimeter Weld 3,160 pieces $ 45.00 $ 142,200

assumes continuous welds

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Gases and materials 2.00 lot $ 5,000.00 $ 10,000

Net Material Cost, Bottom Panels $ 160,683

Add New Bottom Stiffening 36,097 kg Shape preparation, nesting, cutting and edge preparation * Assume 2 hours to prepare nesting, check CNC data, and position the shape * Cut Plate, prepare edges -- 1 hours per shape (15% nesting factor) * Weld plate in place; assumes backing structure was positioned prior Welding set at 6 meters/hour for a 2-person team.

# of Units Unit Cost Total Cost Shape Cost 41,512 kg $ 3.30 $ 136,989 Plasma Cutting Assumes 315.00 Shapes 315 shapes $ 135 $ 42,525 Weld Plate In Place Line Weld 8,131 meters $ 15 $ 121,968 Edge Welds 480 meters $ 15 $ 7,200 assumes continuous welds

Gases and materials 0.50 lot $ 5,000 $ 2,500

Net Material Cost, Bottom Stiffening $ 311,182

DECK TIE-DOWN ADDITIONS 115 @ 70,000# capacity each 320 @ 17,000# capacity each 460 Grade 5 bolts, 5/8" Dia, 60mm or greater length 1300 Grade 5 bolts, 1/2" Dia, 60mm or greater length 435 Gaskets

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# of Units Unit Cost Total Cost Lay-out Deck for tie-downs 40.00 Hours $ 45.00 $ 1,800

Set-up, Drill 5/8" Holes 10mm Pl 460 Holes 15 Minutes/Hole 1 Person/Team 115 Hours 45 $ 5,175

Set-up, Drill 1/2" Holes 10mm Pl 1300 Holes 15 Minutes/Hole 1 Person/Team 325 Hours 45 $ 14,625

Set-up assumed to use cloverleaf as template and drill guide; pilot hole then master hole. Each hole is a one person operation; 15 minutes per hole

Install Cloverleafs 435 Cloverleafs 40 Minutes/Cloverleaf 2 Person/Team 580 Hours 45 $ 26,100

Assumed as a 2 person operation, one below decks to affix washer and nut. Assumed normal torque and tools. Assumed 30 minutes for set-up; bolt; check-out An additional 10 minutes per cloverleaf, average, was assigned to perform required 10mm webframe grinding and inspection prior to cloverleaf installation

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Materials -- 70k# Cloverleaf 115 $ 500.00 ea $ 57,500 Materials -- 17k# Cloverleaf 320 $ 121.43 ea $ 38,857 Materials -- 5/8" Grade 5 Bolt 460 $ 0.50 ea $ 230 Materials -- 1/2" Grade 5 Bolt 1,300 $ 0.29 ea $ 377 Materials -- Gaskets 435 $ 2.50 ea $ 1,088 Materials -- 5/8" Grade 5 Nut 460 $ 0.21 ea $ 97 Materials -- 1/2" Grade 5 Nut 1,300 $ 0.17 ea $ 221 Materials -- 5/8" Washers 460 $ 0.28 ea $ 129 Materials -- 1/2" Washers 1,300 $ 0.13 ea $ 170 Sub-Total, Materials $ 98,669

TOTAL, DECK TIE DOWN INSTALLATION $ 146,369

ABS SLAM LOAD - OPEN OCEAN, UNRESTRICTED OUTFITTING SERVICES * Bottom preparation and painting after installation of the new plating. * Interior tank treatments * Assumes no hull insulation in way of the tanks or deck mounted tie-downs is disturbed. * Area of the stiffeners calculated from the shapes 855 M2 * Assume paint 50M2/Hour per team * Paint cost of $25/sq m is based on military naval bottom paint based on ablative technologies. The cost per gallon is derived from HAYSTACK [subscription account for online access to DoD inventory and procurement costs] and averaged $500/gallon. Coverage is based on the conservative end of vendor data.

BOTTOM PAINT # of Units Unit Cost Total Cost Bottom painting - 2 coats; 2 man spray team Mobile Lift 2 Days $ 250.00 $ 500 Plate Paint, 2 coats, 20 sq m/Gall 300 sq m $ 25.00 $ 7,500 300 sq m $ 25.00 $ 7,500 Labor 32 Hours $ 45.00 $ 1,440 Sub-Total $ 16,940

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TANK PREPARATION # of Units Unit Cost Total Cost Painting, 2 coats epoxy or equal Plate Paint, 2 coats, 20 sq m/Gall 600 sq m $ 25.00 $ 15,000 Stiffener Paint, 2 coats, 20 sq m/Gall 1,710 sq m $ 25.00 $ 42,750 Labor 46 Hours $ 45.00 $ 2,079 Sub-Total $ 59,829 TOTAL, OUTFITTING SERVICES $ 76,769

DNV SLAM LOAD - OPEN OCEAN, UNRESTRICTED OUTFITTING SERVICES * Bottom preparation and painting after installation of the new plating. * Interior tank treatments * Assumes no hull insulation in way of the tanks or deck mounted tie-downs is disturbed. * Area of the stiffeners calculated from the shapes 4,879 M2 * Assume paint 50M2/Hour per team BOTTOM PAINT # of Units Unit Cost Total Cost Bottom painting - 2 coats; 2 man spray team Mobile Lift 2 Days $ 250.00 $ 500 Plate Paint, 2 coats, 20 sq m/Gall 726 sq m $ 25.00 $ 18,150 726 sq m $ 25.00 $ 18,150 Labor 32 Hours $ 45.00 $ 1,440 Sub-Total $ 38,240

TANK PREPARATION # of Units Unit Cost Total Cost Painting, 2 coats epoxy or equal Plate Paint, 2 coats, 20M2/Gall 1,452 sq m $ 25.00 $ 36,300 Stiffening Paint- 2 coats, 20M2/Gall 9,757 sq m $ 25.00 $ 243,936 196

Labor 224 Hours $ 45.00 $ 10,088 Sub-Total $ 290,324 TOTAL, OUTFITTING SERVICES $ 328,564

FACILITIES COSTS This element of the cost estimate captures the costs of dry-docking the vessel, crane and rigging operations to lift out and install the stiffening and plating, firewatch and security functions, waste removal, and other services.

DRY-DOCKING * Assumed a 3 week dry-dock period; 1 week to remove the plate, 2 weeks to install the new stiffening and plate, as well as bottom preparation and float-off. * Assume interior work will be accomplished after float-off * Assumes a rather large dry-dock given the beam of the subject vessel. A dock similar to the Alabama at Alabama Dry-Dock was used in this estimate.

Item Units Rate Cost Docking Calculation 80 Hrs $ 80 $ 6,400 Dry-Docking 21 Days $ 10,000 $ 210,000 Sub-Total $ 216,400

OUTFITTING PIER * Assumed a 3 week post dry-dock period to refurbish interior compartments

Item Units Rate Cost

Pier Side, Post Docking 21 Days $ 1,000 $ 21,000 Sub-Total $ 21,000

SERVICES * Electrical Power, Fluids services are assumed to be negligible as "normal" loads and services are contained within the daily rates. * 2 man roving firewatch assumed for nite shift; day-shift firewatch is integral to the working teams. 197

* 2 man security detail for nite shift, dedicated to the ship/dry-dock * Weekly removal of 1 commercial dumpster with typical waste, $600/week * Material scrapping assumed to be within the yard and a net $0 cost. * Also covers tank gas-free and inerting functions Item Units Rate Cost Firewatch 504 Hrs $ 45 $ 22,680 Security 504 Hrs $ 45 $ 22,680 Waste Removal 5 Weeks $ 599 $ 2,995 Tank Gas Free Service 12 tanks $ 500 $ 6,000 Sub-Total $ 54,355

RIGGING OPERATIONS * Assumes a mobile Lattice-Boom Crane of sufficient capacity to reach out with a 10LT Load. This would come with a driver, spotter and 2 riggers. * Estimated as a commercial daily rental; assumes 3 weeks of use. * Costs taken from MEANS Estimating handbooks, scaled to 2004/2005 rates Item Units Rate Cost Crane 21 Days $ 1,216 $ 25,541 Crew 21 Days $ 1,440 $ 30,240 Sub-Total $ 55,781

TOTAL, FACILITIES COSTS $ 347,536

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8.0 CONCLUSIONS ON REQUIRED ABS AND DNV STRUCTURAL MODIFICATIONS

The nominal hull girder and vehicle deck structure is adequate to handle the increased loading requirements for the unrestricted, open-ocean notation for both ABS and DNV. ABS HSNC requires only limited modifications to resist slam loads whereas DNV criteria require nearly 30 metric tonnes of additional structural weight to satisfy their secondary slamming criteria. The structural modifications to satisfy ABS is approximately 2 metric tonnes.

This report recognizes that both ABS and DNV typically require model tests to confirm final loads for the structural design of any high speed craft. It is certainly possible that such tests would produce design loads more demanding than those predicted by either set of design algorithms and that all conclusions developed through this report need to be tempered with this recognition.

Another factor in the performance of the PacifiCat hull girder structure is a relatively deep hull girder resulting from two vehicle decks. Many fast ferries only have one vehicle deck and the presence of the second vehicle deck results in a strength deck that is one deck higher than usual and an associated hull girder that is also that much deeper than usual. Naturally, this results in greater hull girder inertias and section modulii to resist longitudinal, transverse and torsional bending moments acting on the vessel.

Structural optimization is possible as was demonstrated through the FEA developed for this portion of the task. If an owner should consider increasing class to handle the open-ocean, unrestricted operation it is possible that any weight gain nominally included through application of the rule loads could be offset by optimizing the structure with more refined analysis and FEA.

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9.0 REFERENCES

1. ABS Rules for Building and Classing High Speed Naval Craft, 2003.

2. DNV Rules for Classification of High Speed, Light Craft and Naval Surface Craft, January 2002.

3. Marine Lifting and Lashing Handbook, Second Edition, MTMCTEA REF 97-55-22, October 1996.

4. ABS Guide for Building and Classing High-Speed Craft, February 1997.

5. Medium Tactical Vehicle Replacement (MTVR) Report, John J. McMullen Associates, Inc., June 2000.

6. 1997 Formulas for Stress and Strain, Roark, Raymond J., Young, Warren C., McGraw-Hill Book Company, Fifth Edition, 1982.

7. Design of Welded Structures, Blodgett, Omar, W., The James F. Lincoln Arc Welding Foundation, 1966.

10.0 DRAWING REFERENCS

8. Midship Section – Ship #3 At Frames 28 and 43, Catamaran Ferries International, Drawing # S101 MIDSHIP, REV O.

9. Structural Profiles – Plate Seams Aft, INCAT Designs – Sydney, Drawing # 1811/2-42 Sheet 1 of 2, REV I.

10. Structural Profiles – Plate Seams Forward, INCAT Designs – Sydney, Drawing # 1811/2-42 Sheet 2 of 2, REV H.

11. Structural Profile – Longitudinal Structure, Aft End, INCAT Designs – Sydney, Drawing # 1811/2-43 Sheet 1 of 2, REV F.

12. Structural Profile – Longitudinal Structure, Forward End, INCAT Designs – Sydney, Drawing # 1811/2-43 Sheet 2 of 2, REV F.

13. Struct, Vehicle Decks & Hull Bottom, INCAT Designs – Sydney, Drawing # 1811/2-44 Sheet 1 of 5, REV B.

14. Struct, Vehicle Decks & Hull Bottom, INCAT Designs – Sydney, Drawing # 1811/2-44 Sheet 2 of 5, REV D.

15. Struct, Vehicle Decks & Hull Bottom, INCAT Designs – Sydney, Drawing # 1811/2-44 Sheet 3 of 5, REV H.

200

16. Struct, Vehicle Decks & Hull Bottom, INCAT Designs – Sydney, Drawing # 1811/2-44 Sheet 4 of 5, REV I.

17. Struct, Vehicle Decks & Hull Bottom, INCAT Designs – Sydney, Drawing # 1811/2-44 Sheet 5 of 5, REV E.

18. Jet Duct Structural Profile and Plan, INCAT Designs – Sydney, Drawing # 1811/2-59, REV C.

19. Material Stock List, INCAT Designs – Sydney, Drawing # 1811/2-201, REV D.

201

APPENDIX A.

COMPREHENSIVE LOAD LISTS

A-1

UNITED STATES MARINE CORPS MARINE EXPIDTIONARY UNIT ASSETS

TOTAL TAMCN NOMENCLATURE QTY LN WD HT WT SQ. FT.

MEU COMMAND ELEMENT A0966 AN/MLQ-36 MOBILE ELECTRONIC 1 255 99 126 28,000 175 A1935 RADIO SET AN/MRC-138B 4 185 85 82 5,190 437 A1957 AN/MRC-145 4 185 85 93 5,190 437 C4154 INFLATABLE BOAT RIGID HULL 2 468 98 80 6,000 637 C4433 CONTAINER, QUADRUPLE 15 57 98 82 6,500 582 D0080 CHASSIS TRLR GEN PURPOSE, M353 1 187 96 48 2,720 125 D0085 CHASSIS, TRAILER 3/4 TON 2 147 85 35 1,340 174 D0850 TRAILER CARGO 3/4 TON M101 4 147 75 35 1,340 302 D1059 TRUCK, CARGO 1 316 98 116 28,950 215 D1158 TRUCK UTIL, HMMWV 6 180 85 72 5,200 638 D1180 TRUCK UTILITY 2 180 85 72 5,200 213

TOTAL SQFT 3,935

GROUND COMBAT ELEMENT

A1935 RADIO SET AN/MRC-138B 4 185 85 82 5,190 437 A1937 RADIO SET, MRC145A 9 185 85 83 5,190 983 B0589 AMORED EARTHMOVER, ACE M-9 2 243 110 96 54,000 371 B2482 TRACTOR, ALL WHL DRV W/ ATACH 1 277 94 141 13,000 181 B2566 FORKLIFT 1 196 78 79 11,080 106 B2567 TRAM 1 308 105 132 35,465 225 C4433 CONTAINER, QUADRUPLE 84 57 98 82 6,500 3,259 D0085 CHASSIS, TRAILER, 3/4 TON 1 147 85 35 1,340 87 D0850 TRAILER CARGO 3/4 TON M101 13 147 74 35 1,340 982 D0860 TRAILER CARGO 10 167 83 53 2,670 963 D0880 TRAILER TANK WATER 400GL 1 161 90 77 2,530 101 D1059 TRK, CARGO 17 316 98 116 28,950 3,656 D1072 DUMP TRK 2 316 98 116 31,888 430 D1161 VEH, INTER TRANSPORTABLE 8 194 65 73 4,200 701 D1125 TRK, UTILITY 8 180 85 69 7,098 850 D1158 TRK, UTIL, HMMWV M1038 11 180 85 72 5,200 1,169 D1158 TRK, UTIL, HMMWV M998 39 180 85 72 5,200 4,144 D1159 TRK, UTIL, ARMT CARR HMMV 12 180 85 69 5,977 1,275 E0665 155MM HOWITZER 6 465 99 115 15,400 1,918 E0796 AAAV COMMAND (C-7) 1 360 144 126 72,500 360 E0846 AAAV PERSONNEL (P-7) 14 360 144 126 72,500 5,040 E0942 LAV ANTI TANK (AT0 2 251 99 123 24,850 345 E0946 LAV C2 1 254 99 105 26,180 175 E0947 LAV ASSULT 25MM 11 252 99 106 24,040 1,906

A-2

TOTAL TAMCN NOMENCLATURE QTY LN WD HT WT SQ. FT.

E0948 LAV LOGISTICS (L) 1 255 98 109 28,200 174 E0949 LAV, MORTAR CAR 2 255 99 95 23,300 351 E0950 LAV, MAINT RECOV 1 291 99 112 28,400 200 E0996 BLADE MINE CLEARING 1 179 115 29 9,000 143 E1888 TANK, M1A1 4 387 144 114 128,600 1,548

TOTAL SQ FT 32,080

COMBAT SERVICE SUPPORT EQUIPMENT

A1935 RADIO SET AN/MRC-138B 2 185 85 82 5,190 218 A1957 AN/MRC-145 2 185 85 82 5,190 328 B0215 BUCKET, GEN PURP, 2 1/2 YD 2 108 50 50 2,910 75 B0395 COMPRESSOR AIR 250CFM 3 214 97 83 8,390 433 B0579 LOAD BANK, DA543/G 1 187 96 67 4,800 125 B0591 EXCAVATOR HYD WHL 1085C 1 365 97 154 40,960 246 B0635 FLOODLT SET SKID MTD SM 4A30 4 134 43 66 2,000 160 B1220 KIT ASSAULT TRACKWY (MOMAT) 12 96 60 60 4,000 480 B2561 TRUCK, FORKLIFT 2 315 102 101 25,600 446 B2566 FORKLIFT 4000 LBS 2 196 78 79 11,080 212 B2567 TRAM 4 308 105 132 35,465 898 B2685 WELD MACHINE, ARC, TRL-MTD 1 186 96 88 8,100 124 C4433 CONTAINER, QUADRUPLE 50 57 98 82 6,500 1,940 D0080 CHASSIS TRLR GEN PURPOSE, M353 6 187 96 48 2,720 748 D0085 CHASSIS, TRAILER, 3/4 TON 6 147 85 35 1,340 521 D0209 POWER UNIT, FRONT (LVS) MK-48 13 239 96 102 25,300 2,072 D0850 TRAILER CARGO 3/4 TON M101 2 147 74 35 1,340 151 D0860 TRAILER CARGO 1-1/2 TON M-105 6 167 83 53 2,670 578 D0860 TRAILER CARGO 1-1/2 TON M-105 1 167 83 53 2,670 96 D0876 TRLR, POWERED, MK-14 7 239 96 50 16,000 1,115 D0877 TRLR, POWERED, MK-15 1 240 96 96 26,000 160 D0879 TRLR, POWERED, MK-17 2 240 96 96 22,650 320 D0880 TRAILER TANK WATER 400 GL 4 161 90 77 2,530 403 D1001 TRUCK AMB 4 LIT ARMD 1 1/4 TON 4 180 85 73 4,960 425 D1059 TRUCK, CARGO 25 316 98 116 28,950 5,376 D1061 TRUCK M- 927 5 TON EXT BED 4 404 98 116 31,500 1,100 D1072 DUMP TRUCK 1 316 98 116 31,888 215 D1158 TRUCK UTIL HMMWV 5 180 85 72 5,200 531 D1159 TRUCK UTIL, HMMWV M1044 3 180 85 69 7,098 319 D1159 TRUCK UTIL, HMMWV M1043 2 180 85 69 7,098 213 D1193 TRUCK, 5-TON, M934A1 1 346 98 114 38,466 236 D1212 TRUCK WRECKER 5 TON 6X6 2 346 98 114 38,466 471 E1377 REC VEH, FULL TRACK M88A1 1 339 144 117 139,600 339

A-3

TOTAL TAMCN NOMENCLATURE QTY LN WD HT WT SQ. FT.

E1712 SHOP SET, MOBILE ARTY 1 240 96 96 8,000 160 E1713 OPT MAINT SHELTER 20 FT 1 240 98 98 10,000 163

TOTAL SQ FT 21,397

AVIATION COMBAT ELEMENT

A1935 RADIO SET AN/MRC-138B 2 185 85 82 5,190 218 A1957 AN/MRC-145 1 185 85 82 5,190 109 C4433 CONTAINER, QUADRUPLE 19 57 98 82 6,500 738 D0085 CHASSIS, TRAILER, 3/4 TON 2 147 85 35 1,340 174 D1158 TRUCK UTIL, HMMWV M1038 4 180 85 72 5,200 425 E1836 AVENGER VEHICLE (CLAWS) 3 185 109 98 9,000 420 D1061 MTVR 7 TON EXT BED 3 404 98 116 31,500 825

TOTAL SQ FT 2,909

MAGTF TOTALS

MAGTF ELEMENT TOTAL

COMMAND ELEMENT 3,935 GROUND COMBAT ELEMENT 32,080 COMBAT SERVICE SUPPORT 21,397 ELEMENT AVIATION COMBAT ELEMENT 2,909

TOTAL SQ FT 60,321

A-4

UNITED STATES ARMY STRYKER BRIGADE COMBAT TEAM

Model Quantity Veh Length Width Height Weight SqFt STons Veh (IN) 1650-EH-MS 3 72 10 72 110 15 0 OE-239/GSQ 4 42 40 40 45 47 0 AN/TPQ-37V 1 90 78 72 2196 49 1 AN/TPQ-37V 1 196 96 92 10855 131 5 AN/TPQ-37V 1 181 96 64 7866 121 4 M3 (SUMMA) 2 234 92 51 11040 299 11 M3 (SUMMA) 19 234 92 85 18400 2841 175 MED GIRDER 1 205 93 67 6306 132 3 MED GIRDER 5 179 83 53 4756 516 12 MED GIRDER 1 161 87 65 4356 97 2 MED GIRDER 1 125 63 69 6212 55 3 MED GIRDER 1 124 68 43 5841 59 3 MED GIRDER 1 134 87 43 2273 81 1 MED GIRDER 1 156 74 70 6720 80 3 100-FT LG 1 186 82 82 7200 106 4 100-FT LG 1 186 82 83 7400 106 4 100-FT LG 1 176 82 86 6500 100 3 100-FT LG 1 176 82 82 6400 100 3 100-FT LG 1 176 82 80 6400 100 3 100-FT LG 5 176 82 77 9000 501 23 100-FT LG 1 186 82 72 7200 106 4 100-FT LG 1 176 82 89 7200 100 4 100-FT LG 1 176 82 83 7600 100 4 100-FT LG 1 178 89 68 6000 110 3 100-FT LG 1 178 82 86 6300 101 3 100-FT LG 1 178 82 90 7100 101 4 100-FT LG 1 178 82 40 6000 101 3 100-FT LG 1 186 83 62 7000 107 4 SET AN/TSM-153 1 147 87 84 2501 89 1 NONE 6 239 96 96 8000 956 24 NONE 13 96 96 46 3020 832 20 NONE 13 44 43 39 1755 171 11 M139 3 94 32 15 500 63 1 M139 3 94 32 15 425 63 1 WTR 500 GA 36 78 36 25 400 702 7 AN/TSM-210 1 123 89 72 3782 76 2 1/2 T M200A1 9 R 169 94 41 2445 993 11 C-20X-8016 3 65 25 40 610 34 1 40 AM NONE 3 60 36 36 400 45 1 60 AM NONE 10 60 36 36 400 150 2 AN/GYK-37V 13 147 87 84 5893 1155 38

A-5

Model Quantity Veh Length Width Height Weight SqFt STons Veh (IN) AN/GYK-37V 13 147 87 84 3911 1155 25 NONE 1 84 48 48 700 28 0 MEP-802A 25 50 32 36 825 278 10 MEP-806B 1 87 36 59 3992 22 2 MEP-804A 1 70 36 54 2500 18 1 MEP-804A 2 R 139 87 85 4080 168 4 PU-806B/G 1 R 165 95 87 6813 109 3 MEP-816B 1 87 36 59 4042 22 2 PU-803B/G 4 R 165 95 84 5700 435 11 PU-751/M 1 R 144 74 79 2840 74 1 PU-753/M 1 R 144 74 78 2525 74 1 PU-798 1 R 147 84 76 2570 86 1 PU-798A 15 R 135 86 67 2480 81 19 PU-798 2 R 147 84 78 2830 172 3 PU-799A 1 R 135 86 67 2510 81 1 PU-799 1 R 147 85 77 3040 87 2 PU-802 17 R 165 95 84 4920 1851 42 500 GAL CA 42 74 35 18 233 755 5 MEP-803A 19 62 32 37 1250 262 12 MEP-813A 1 62 32 36 1280 14 1 NONE 13 65 40 58 355 235 2 AN/ASM-146 10 147 87 84 3664 888 18 AN/ASM-147 4 147 87 84 3962 355 8 AN/GRC-193 RADIO 2 27 20 40 130 8 0 NONE 14 81 39 35 840 307 6 148002-1 1 73 30 37 1720 15 1 AN/TSC-116 3 83 82 39 950 142 1 MK-2727/G 15 96 53 108 201 530 2 TYPE-2 20 48 40 48 330 267 3 TYPE-2 20 48 40 48 422 267 4 M198 12 R 496 111 117 15750 4588 95 MKT-95 1 R 201 152 132 5260 212 3 NONE 6 R 187 96 71 6109 748 18 M121 36 R 95 60 45 720 1425 13 AN/MJQ-35A 2 R 135 86 66 3140 161 3 M59 22 27 24 42 253 99 3 M93A1 FOX 3 R 288 118 105 38500 708 58 CE-11 270 6 24 36 32 270 4 NONE 2 41 31 55 384 18 0 NONE 14 50 36 36 530 175 4 LP/PD1-90 22 102 84 71 3930 1309 43 S250 12 87 79 70 770 573 5 TY3 8 102 89 67 680 504 3

A-6

Model Quantity Veh Length Width Height Weight SqFt STons Veh (IN) TY3 1 140 84 70 3249 82 2 NONE 17 R 191 89 99 9200 2007 78 NONE 11 49 27 38 41 101 0 NONE 11 56 26 38 57 111 0 NONE 1 73 20 34 150 10 0 MST F/VOLC 2 20 17 43 19 5 0 M1097 1 R 191 86 72 5600 114 3 M1097 3 R 197 86 102 9220 353 14 M1097 3 R 197 86 102 9165 353 14

M1097 1 R 199 89 82 7980 123 4 M1097 1 R 216 86 102 8620 129 4 M1097 1 R 202 94 102 9236 132 5

M1097 1 R 207 84 102 8326 121 4 M1097A2 76 R 191 91 72 5900 9173 224 M1097A2 1 R 191 86 56 5900 114 3 M1097A2 1 R 191 86 102 10214 114 5 NONE 2 101 79 70 2740 111 3 SET N 2 73 26 36 225 26 0 SET N 2 101 12 8 183 17 0

FIELD MAIN 2 239 96 96 18687 319 19 FM SUPPL N 2 148 88 84 9219 181 9 ADC 1000 1 R 151 79 76 2860 83 1 NONE 1 239 96 96 8490 159 4 FLU-419 6 R 250 96 102 15920 1000 48 NONE 2 55 25 37 268 19 0 NONE 2 25 21 36 158 7 0 M997A2 27 R 205 86 102 7660 3306 103 M1083A1 WW 26 R 274 96 112 23700 4749 308 M1084A1 WO 15 R 306 96 112 25373 3060 190 AN/TSM-174 1 67 55 40 485 26 0 LME 13 96 49 35 990 425 6 M978 WWN 4 R 401 96 112 38165 1069 76 NONE 2 27 42 50 70 16 0 M998 1 R 187 84 53 5280 109 3 M998 1 R 187 84 53 5280 109 3 M998A1 294 R 180 86 72 5380 31605 791 M1038A1 WW 2 R 186 86 72 5507 222 6 M1113 WWN 26 R 191 98 72 6380 3380 83 M1113 WWN 2 R 220 89 102 10066 272 10 M1085A1 WO 2 R 349 96 112 23973 465 24

A-7

Model Quantity Veh Length Width Height Weight SqFt STons Veh (IN) M1083A1 WO 120 R 274 96 112 22723 21920 1363 M984A1 WWN 17 R 402 102 112 51300 4841 436 (ATLA 10000 LBS 8 NR 349 101 107 33120 1958 132 HI SP DUECE 6 NR 230 107 109 35750 1025 107 AN/TSC-154 3 111 85 50 2530 197 4 M978 WOWN 10 R 401 96 112 38165 2673 191 M1977 WOWN 4 R 395 97 113 37240 1064 74 M1025A2 8 R 191 86 74 6780 913 27 M1114 7 R 197 86 72 9800 824 34 M1076 58 R 324 96 124 16530 12528 479 M1095 51 R 230 96 82 9202 7820 235 M1102 55 R 136 86 100 1400 4467 39 M1102 1 R 136 86 86 4114 81 2 M1102 1 R 136 86 86 3652 81 2 M1101 191 R 136 86 100 1400 15513 134 XM1120 WOW 56 R 401 96 129 35300 14971 988 M1082 1 R 210 96 79 6860 140 3 COMMON NO 1 167 87 84 4460 101 2 NONE 1 R 179 96 97 7355 119 4 NONE 1 76 33 8 157 17 0 NONE 1 75 28 41 515 15 0 NONE 1 76 28 41 530 15 0 M105A2 1 R 166 83 82 6280 96 3 M1112 67 R 163 98 84 3945 7432 132 2-1/2-TON 1 R 281 100 128 19480 195 10 M116A2 1 R 147 85 77 2940 87 1 M1102 3 R 170 85 86 3710 301 6 ATG 1 R 161 85 87 3149 95 2 AVT 1 R 217 85 105 11431 128 6 GCS1 1 R 208 85 105 11310 123 6 LRT 1 R 166 87 70 4188 100 2 TC1 1 R 208 85 72 9775 123 5 GCS2 1 R 208 85 105 9360 123 5 ET 1 R 131 85 96 3842 77 2 MMF 1 R 218 85 105 10562 129 5 MMFT 1 R 131 85 96 3831 77 2 TC2 1 R 208 85 72 9775 123 5 NONE 3 63 2 63 3 3 0 MECC 2 240 94 96 4000 313 4 NONE 5 240 96 96 15000 800 38 ESV 9 R 283 110 106 42000 1946 189 CV 27 R 283 110 106 42000 5837 567 FRS-L 12 240 96 96 24000 1920 144

A-8

Model Quantity Veh Length Width Height Weight SqFt STons Veh (IN) STRYKER 108 R 288 113 106 42000 24408 2268 MGS 27 R 301 105 106 41300 5926 558 MC 36 R 277 117 104 42000 8102 756 AN/GRC-229 10 45 2 45 5 6 0 FSV 13 R 283 111 106 42000 2836 273 MEV 16 R 277 117 94 42000 3601 336 AN/TSQ158- 3 206 87 90 6235 373 9 RCV 48 R 283 113 106 42000 10660 1008 ATGM 9 R 283 111 104 42000 1963 189 Supply 42475 264 21 ------10578 28 5 TOE * 1375544 8085 688

2969617 272607 14403

148481 13630.4 720.15

A-9

APPENDIX B.

DETAILS OF CANDIDATE VESSELS

B-1

INCAT 91m – Spec Sheet provided by INCAT website as “63250_2091mwpc-ropax-onepage-001.doc” General Particulars Life Saving and Evacuation Builder Incat Tasmania Pty Ltd. Escape - Four Marine Evacuation Stations, two port and two Class Society Det Norske Veritas starboard, and two external stairs aft. The two forward MES serve a Certification DNV +1A1 HSLC R1 Car Ferry “B” EO total of 100 persons each, the two mid MES serving a total of 200 Length overall 91.30m persons each and one aft stair serving 200 persons and one aft stair Length waterline 81.33m serving 100 persons. A total of ten x 100 person rafts are fitted. Beam overall 26.00m Rescue - Two SOLAS inflatable rescue dinghy with 30 hp motor and Beam of Hulls 4.50m approved launch / recovery method. Draft 3.73m approx. in salt water Service Speed 42 knots Lifejackets with lights for full compliment fitted under seats and in Lightship Speed 48 knots storage cabinets. *Note - All speeds quoted at 100% MCR (4 x 7080kw @ 1030 rpm) Safety Equipment - Liebuoys with lights and lines, smoke flares, and excluding T-foil. Immersion suits, flares and lines throwing device fitted in accordance Capacities with international regulations Max Deadweight 510 tonnes (maximum available dependent on Fire Safety building specification). Fire Detection - An addressable fire detection system covers at Total persons up to 900 persons minimum all high and moderate risk spaces (other than the Vehicle Capacity 220 cars at 4.5m length x 2.3m wide or wheelhouse) with alarm panel situated in the wheelhouse. CCTV combination of cars and up to 4 buses. system covers at a minimum, engine rooms, ante rooms, vehicle Axle loads - Transom to Frame 14 - 9 tonnes per dual wheel axle, spaces, jet rooms, MES and liferafts stations (serving as mooring Frame 14 to 35 - 2 tonnes per axle group and fwd of Frame 35 Ramps cameras) with monitors in the wheelhouse. A to D - 0.8 tonnes per axle group. Fire Sprinklers - Vehicle deck and passenger cabin are protected by Fuel Capacity - 4 x 14m3 integral aluminium tank and additional drencher systems with overhead sprinklers. Pump control is from the long-range tank of minimum 170m3 capacity provided in each hull. wheelhouse and anterooms. Fresh Water 1 x 5.0 m3 GRP tank. General Equipment - Portable fire extinguishers, Fireman’s outfits and Sewage 1 x 5.0 m3 GRP tank. equipment, water fog applicators, breathing apparatus, international Construction connections and fire control plans fitted in accordance with Design - Two slender, aluminum hulls connected by a bridging international regulations. section with center bow structure at fwd end. Each hull is divided into Machinery Installations eight vented, watertight compartments divided by transverse bulkheads. One compartment in each hull prepared as short-range Main Engines - 4 x resiliently mounted Ruston 20RK270 or fuel tanks and one as a long-range fuel tank. Caterpillar 3618 marine diesel engines. Welded and bonded aluminium construction using longitudinal Water Jets - 4 x Lips LJ145D waterjets with steering and reverse. stiffeners supported by transverse web frames and bulkheads. Transmission - 4 x Renk ASL60 gearboxes, approved by the engine Aluminum plate grade 5383 H321 or H116. Aluminium extrusions manufacturer, with reduction ratio for optimum jet shaft speed. grade 6082 T6 and 5083 H112. Ride Control - A ‘Maritime Dynamics’ active ride control system is Passenger Accommodation fitted to maximise passenger comfort. The system combines active Superstructure - Passenger accommodation supported above the trim tabs aft and optional bolt-on T-foil located at the forward end of vehicle deck on anti-vibration mounts. each hull. Outfit – All materials comply with IMO standards for fire, low flame Electrical Installations spread, smoke and toxicity. Alternators – 4 x Caterpillar 3406B 230kw Public Address - Builder’s standard, marine, public address system Distribution - 415V, 50 Hz. 3 phase. 4 wire distribution with neutral supplied and fitted to cover all passenger and crew areas, vehicle earth allowing 240 volt supply using one phase and one neutral. decks, stairwells and ante rooms. Colour tvs fitted throughout the Distribution via distribution boards adjacent to or within the space passenger cabin to enable seated view of safety messages and video. they serve.

B-2

INCAT 96m - EVOLUTION 10 - 96m Wave Piercing Ro/Pax Catamaran

Yard No. - 051 Builder - Incat Tasmania Pty Ltd Class Society - Det Norske Veritas Applicable Regulations - DNV HSLC Rules current at the date of contract. - IMO HSC Code and applicable IMO Regulations at date of contract. Certification - DNV ?1A1 HSLC R1 Car Ferry “B” EO Certificate Length overall - 95.47m Length waterline - 86.00m Beam overall - 26.60m Beam of Hulls - 4.50m Draft loaded - 4.03m Speed - 38 knots at 868 tonnes deadweight - 47 knots at Lightship *Note - All speeds quoted at 100% MCR 4 x 7080 KW @ 1030 rpm excluding T-foil. Max Deadweight - 868 tonnes Total persons - 750 maximum Vehicle Deck Capacity - 330 truck lane metres at 3.1m wide x 4.0m/4.35m clear height plus 80 cars at 4.5m length x 2.3m width or maximum 230 cars only. Axle loads - Transom to Frame 47 - 10 tonnes per dual wheel axle or axle groups to suit European standards. Fwd of Frame 47 Ramp A to D and Optional Mezzanine Decks - 0.8 tonnes per axle. Fuel Capacity - 4 x 43,720 litre integral aluminium tanks and 2 x 196,428 litre long-range tanks. Fresh Water - 1 x 5000 litre GRP tank. Sewage - 1 x 5000 litre GRP tank. Lube Oil - 2 x 465 litre aluminium tanks. Structures Design - Two slender, aluminum hulls connected by a bridging section with center bow structure at fwd end. Subdivision - Each hull is divided into eight vented, watertight compartments divided by transverse bulkheads. Two compartments in each hull prepared as short range fuel tanks and one as a long range fuel tank. Fabrication - Welded and bonded aluminum construction, with longitudinal stiffeners supported by transverse web frames and bulkheads. Aluminum plate grade 5383 H116 or 5518 H116 and extrusion grade 6082 T6 and 5083 H112. Passenger Accommodation and Escape Wall Coverings - Ayrlite 2005 laminated pre-finished composite board. Floor Coverings - 80:20 tufted carpet and selected chlorine-free vinyl type flooring adhered to decks with epoxy adhesive. Ceilings - Luxalon 300C aluminium linear ceiling, cotton white, with 75mm semi-circular trim between every three panels or Luxalon 180 B aluminium linear ceiling. Windows - Combination of Incat “Glass Only” window installation system with toughened glass and aluminium framed sliding windows where required. Lighting - Peirlite 18W PL tube recessed downlights and Staff recessed low voltage 12v 50W downlight with dichoric lamps.

B-3

Air Conditioning - Sanyo model SPW-XC 483 throughout capable of maintaining between 20-22 deg C and 50% RH with a full passenger loads and ambient temperature of 32 deg C and 50% RH Ventilation System - Supply fans will provide fresh air into the Pax area at a rate of 3 air changes per hour. Pantry, Kiosk, Bar, and Toilet exhaust fans provide 30 air changes per hour within the space. Purge and exhaust fans will purge the air from the Pax space at the rate of 6 air changes per hour Aircraft Seating - Beurteaux Ocean Tourist high back reclining and fixed seats with open arm rest, magazine holders, folding meal table, under-seat life jacket holders and wool fabric upholstery with leather trim. Lounges - Beurteaux Tub seats with wool fabric upholstery and leather trim. Bar Stools - Incat Bar stools with selected wool fabric upholstery, stainless steel pillar and footrest. Passenger Access - Four stairways from the vehicle deck offer entry to Pax area. Two fwd and two amidships plus disability access ramp from forward vehicle deck. - Shore access via two dedicated passenger gangway gates port and stbd at the pax level aft. Public Address - Builder’s standard public address system to cover all passenger and crew areas, vehicle decks, stairwells and anterooms. Colour televisions fitted throughout the passenger cabin configured to receive video, safety messages and input from the electronic chart system. Alarm - Two tone general alarm (seven short and one long) signal generator activated from wheelhouse. Escape - Escape is via Four Marine Evacuation Stations, two port and two stbd. A total of nine 100person rafts are fitted. - 2 x SOLAS inflatable dinghy with 30 hp motor and approved launch / recovery method. Fire Safety Fire Detection - An addressable fire detection system covers at minimum all high and moderate risk spaces (other than the wheelhouse) with alarm panel situated in the wheelhouse with CCTV cameras. Fire Protection - Lightweight structural fire protection protects all moderate and high risk spaces. ER Fire Control - CO2 system for each engine room together with second shot cross connection. Drenchers - Vehicle deck is protected by a zoned drencher system capable of operating two zones simultaneously. Pump control is from the wheelhouse and anterooms. - Pax area is protected by a zoned, dry closed bulb drencher system interconnected with control valves to a single vehicle deck drencher pump. Hydrants - Two electric motor driven pumps, one in Void 2 port and stbd, feed into a common loop which feed fire hydrants distributed throughout the ship. General Equipment - Portable fire extinguishers, Fireman’s outfits and equipment, water fog applicators, breathing apparatus, international connections and fire control plans included to meet rule requirements. Machinery Installations Main Engines - 4 x resiliently mounted Ruston 20RK270 marine diesel engines, each rated at over 7080 kW at 1030 rpm. Water Jets - 4 x Lips LJ150D waterjets configured for steering and reverse. Transmission - 4 x Reintjes VLJ 6831 gearboxes, approved by engine manufacturer, with reduction ratio suited for optimum jet shaft speed. Hydraulics - Three hydraulic power packs, one forward and two aft, for running of mooring capstans, anchor winch, ride control, steering/reverse and rescue boat cranes. Ride Control - A ‘Maritime Dynamics’ active ride control system is fitted to maximise passenger comfort. This system combines, active trim tabs aft and optional fold-down T-foil located at aft end of centre bow fitted with active fins. The structural abutment, electrical and hydraulic services to receive the fwd T-foil will be fitted as standard to the vessel. Trim Tabs - A hydraulically operated trim tab is hinged at the aft end of each hull. Monitoring - An electronic alarm and monitoring system with dual central VDU displays, keyboards and printer fitted in the wheelhouse. Alarm and monitoring to meet the requirements of the HSC Code, the HSLC Rules and EO requirements.

B-4

Communication - A ‘David Clark’ system is fitted to allow communication between the Wheelhouse helm position, Aft vehicle deck, Anchor area, Anterooms, Jet rooms, Engine rooms, T-foil void. All points have call facilities to the wheelhouse via headset stations with volume control. Electrical Installations Alternators - 4 x Caterpillar 3406B 245 kW (nominal) marine, brushless, self-excited alternators. Distribution - 415V, 50 Hz. 3 phase. 4 wire distribution with neutral earth allowing 240 volt supply using one phase and one neutral. Distribution via distribution boards adjacent to or within the space they serve. Switchboards - Main switchboards fitted with a load preferential trip system which automatically sheds non essential loads whilst still maintaining one alternator as a standby set. Each switchboard fitted with a bus coupler breaker to allow the main bus bars to be split in the event of a fault condition. Essential Distribution - Distribution to essential services from independent distribution boards supplied from both switchboards. Shore Power - 60 amp 415V 3 phase outlet fitted in port and stbd anterooms. 24v DC Systems - Separate systems for automation and to power ship’s radio communication. Essential Lighting - 10% of the main light fittings are powered from the essential services distribution board. Essential lights and exit signs fitted as required and indicated by red dot. Navigation Lights - Dual power supply (Main and essential services) controlled from the wheelhouse for all navigation lights including NUC and anchor lights. Cathodic Protection - Sea inlets and jet area protected by high capacity anodes. Hull potential monitoring system, alarmed to the wheelhouse fitted. Operating Compartment Operation - There are three forward facing seats around the centre line. Captain in the centre, Navigator to starboard and Engineer to port. Main Console contains all required navigation, communication and monitoring equipment. Communication - The three onboard communication systems are operable from the wheelhouse, enabling communication to all machinery, mooring and passenger spaces. Navigational Equipment GPS - 2 x Leica Differential GPS Radars - Captain - Bridgemaster X band with 15” True motion performance monitor inc. auto track and geographics - Navigator - Bridgemaster S band with 15” Arpa performance monitor inc. auto track and geographics (Radar interswitching) Autopilot - Lips Gyro Compass - An Schutz Magnetic Compass - Plath Electronic Chart System - Transis Echo Sounder - Skipper Speed / Distance Log - Walker electromagnetic with interface to radar’s, GPS and autopilot. Wind Speed/Direction - Walker Weather Fax / Navtex - Furuno Barometer / Clock - Builders standard Air Horn - Ibuki Daylight Signal Lamp - Aldis Francis Search Light - Mounted on fwd mast with remote control - Den Hann Radio Communications MF / HF Radios - } HF DSC inc. 2187.5 kHz - } Simplex / Semi Duplex VHF Transceivers - } VHF / DSC Controller with Ch.70 Receive - } To comply with GMDSS Sea Area 1 and 2 Hand held transceivers inc. chargers. - } EPIRB (406 Mhz) - } SART - } Satcom C - }

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INCAT Evolution 10 – Spec Sheet provided by INCAT website as “96mwpc-ropax-onepage-004.doc”

General Particulars Air Conditioning Builder Incat Tasmania Pty Ltd. Sanyo model SPW-XC 483 throughout capable of maintaining Class Society Det Norske Veritas between 20-22 deg C and 50% RH with a full passenger loads and Certification DNV +1A1 HSLC R1 Car Ferry “B” EO ambient temperature of 32 deg C and 50% RH Length overall 96.00m Length waterline 86.00m Beam overall 26.60m Evacuation Beam of Hulls 4.50m Escape is via Four Marine Evacuation Stations, two port and two Draft 4.00m approx. in salt water starboard, and two external stairs aft. The two forward MES serve a Speed 38 knots @ 1650 tonnes displacement total of 200 persons each (4 x 100), the two mid MES serve a total 42 knots @ 1400 tonnes displacement of 200 persons each (4x100) and one aft stair serving 100 persons. *Note - All speeds quoted at 100% MCR (4 x 7080kw @ 1030 A total of ten x 100 person rafts are fitted. rpm) and excluding T-foil. 2 x SOLAS inflatable dinghy with 30 hp motor and approved launch / recovery method. Capacities Max Deadweight 675 tonnes (estimate based on building Machinery Installations specification). Main Engines - 4 x resiliently mounted Ruston 20RK270 or Total persons up to 900 persons Caterpillar 3618 marine diesel engines Vehicle Capacity 380 truck lane metres at 3.1m wide x 4.35m clear Water Jets - 4 x Lips LJ150D waterjets configured for steering and height plus 90 cars at 4.5m length x 2.3m wide or 260 cars only reverse. using optional mezzanine decks. Transmission - 4 x Reintjes gearboxes, approved by the engine Axle loads - Transom to Frame 47 - 10 tonnes per dual wheel axle manufacturer, with reduction ratio suited for optimum jet shaft or axle groups to suit European standards. Forward of Frame 47 - speed. Ramp A to D and Optional Mezzanine Decks - 0.8 tonnes per axle. Hydraulics - Three hydraulic power packs, one forward and two aft, Fuel Capacity - 4 x 40m3 integral aluminum tank and additional all alarmed for low level, high temperature and filter clog and low long-range tank of minimum 170m3 capacity provided in each hull. pressure. One pressure line filter and two return line filters fitted. Fresh Water 1 x 5.0 m3 GRP tank. An off-line filter / pump provided. Sewage 1 x 5.0 m3 GRP tank Ride Control - A ‘Maritime Dynamics’ active ride control system is fitted to maximise passenger comfort. This system combines active trim tabs aft and optional fold-down T-foil located at aft end of Construction centre bow fitted with active fins. The structural abutment, Design - Two slender, aluminum hulls connected by a bridging electrical and hydraulic services to receive the fwd T-foil will be section with center bow structure at fwd end. Each hull is divided fitted as standard to the vessel. into eight vented, watertight compartments divided by transverse bulkheads. Two compartments in each hull prepared as short-range Electrical Installations fuel tanks and one as a long-range fuel tank. Alternators – 4 x Caterpillar 3406B 230kw (nominal) marine, Welded and bonded aluminium construction using longitudinal brushless, self-excited alternators. stiffeners supported by transverse web frames and bulkheads. Aluminum plate grade 5383 H116 or 5518 H116. Aluminium Distribution - 415V, 50 Hz. 3 phase. 4 wire distribution with neutral extrusions grade 6082 T6 and 5083 H112. earth allowing 240 volt supply using one phase and one neutral. Distribution via distribution boards adjacent to or within the space they serve.

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INCAT Evolution 10B

Length overall 97.22m Evacuation Length waterline 92.00m Escape is via Four Marine Evacuation Stations, two port and two Beam overall 26.60m starboard, and two external stairs aft. The two forward MES serve a Beam of Hulls 4.50m total of 200 persons each, the two mid MES serve a total of 200 Draft 3.42m maximum persons each and one aft stair serving 100 persons. A total of ten 100person rafts are fitted. Speed 36 knots @ 750 tonnes deadweight 2 x SOLAS inflatable dinghy with 30 hp motor and approved 40 knots @ 375 tonnes deadweight launch / recovery method. *Note - All speeds quoted at 100% MCR (4 x 7080kw @ 1030 rpm) and excluding T-foil. Machinery Installations

Main Engines - 4 x resiliently mounted Ruston 20RK270 or Capacities Caterpillar 3618 marine diesel engines, each rated at 7080 KW. Max Deadweight - 750 tonnes (to be confirmed at time of Water Jets - 4 x Lips 120E waterjets configured for steering and contract) reverse. Total persons - up to 900 persons Transmission - 4 x Reintjes gearboxes, approved by the engine Vehicle Capacity - 380 truck lane metres at 3.1m wide x 4.35m manufacturer, with reduction ratio suited for optimum jet shaft clear height plus 80 cars at 4.5m length x 2.3m wide or 260 cars speed. only using optional mezzanine decks. Hydraulics - Three hydraulic power packs, one forward and two aft, Axle loads – Transom to Frame 49 - 10 tonnes per dual wheel axle all alarmed for low level, high temperature and filter clog and low or axle groups to suit European standards. Forward of Frame 49 - pressure. One pressure line filter and two return line filters fitted. Ramp A to D and Optional Mezzanine Decks - 0.8 tonnes per axle. An off-line filter / pump provided. Fuel Capacity - 4 x 40m3 integral aluminum tank and additional Ride Control - A ‘Maritime Dynamics’ active ride control system is long-range tank of minimum 170m3 capacity provided in each hull. fitted to maximise passenger comfort. This system combines active Fresh Water 1 x 5.0 m3 GRP tank. trim tabs aft and optional fold-down T-foil located at aft end of Sewage 1 x 5.0 m3 GRP tank centre bow fitted with active fins. The structural abutment, electrical and hydraulic services to receive the fwd T-foil will be fitted as standard to the vessel. Construction Design - Two slender, aluminum hulls connected by a bridging Electrical Installations section with center bow structure at fwd end. Each hull is divided into nine vented, watertight compartments divided by transverse Alternators – 4 x Caterpillar 3406B 230kw (nominal) marine, bulkheads. Two compartments in each hull prepared as short-range brushless, self-excited alternators. fuel tanks and one as a long-range fuel tank. Welded and glued Distribution - 415V, 50 Hz. 3 phase. 4 wire distribution with neutral aluminum construction using longitudinal stiffeners supported by earth allowing 240 volt supply using one phase and one neutral. transverse web frames and bulkheads. Aluminum plate grade 5383 Distribution via distribution boards adjacent to or within the space H116 or 5518 H116. Aluminium extrusions grade 6082 T6 and they serve. 5083 H112.

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AUSTAL AutoExpress 101 – from Austal file “ae101-euroferry.pdf”

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INCAT Evolution 112 – Spec Sheet provided by INCAT website as “112mwpc-ropax-onepage-0.doc”

General Particulars Air Conditioning Designer Incat Tasmania Pty Ltd. Sanyo ceiling mounted reverse cycle units capable of maintaining Builder Incat Tasmania Pty Ltd. between 20-22 deg C and 50% RH with a full passenger loads and ambient temperature of 32 deg C and 50% RH Class Society Det Norske Veritas

Certification DNV ?1A1 HSLC R1 Car Ferry “B” EO Evacuation Length overall 112.63 m Escape - Four Marine Evacuation Stations, two port and two Length (hulls) 105.60 m starboard, and two external stairs aft. The two forward MES serve a Beam (moulded) 30.20 m total of 200 persons each (4 x 100), the two mid MES serve a total Beam (hulls) 5.80 m of 200 persons each (4 x 100) and one aft stair serving 200 persons. A total of eleven 100-person liferafts are fitted. Draft 3.30m approx. in salt water Rescue - Two SOLAS inflatable dinghy with 30 hp motor and Speed 40 knots @ 1000 tonnes deadweight approved launch / recovery method. 45 knots @ 500 tonnes deadweight *Note - All speeds quoted at 100% MCR (4 x 9000 kW) and excluding T-foil. Machinery Installations Main Engines - Four resiliently mounted Ruston 20RK280 each Capacities rated at 9000kW at 100% MCR at 25 deg C ambient temperature. Deadweight - 1000 tonnes (1500 tonnes ‘cargo only’ at reduced Water Jets - Four Lips 150E waterjets configured for steering and speed). reverse. Passengers capacity - up to 1000 persons Transmission - Four Gearboxes approved by the turbine Vehicle Capacity - 589 truck-lane metres at 3.5m wide plus 50 cars manufacturer, with reduction ratio suited for optimum jet shaft at 2.3m wide or 321 cars only. speed. Vehicle Deck Clear Heights - 6.30m centre vehicle deck, 5.95m Hydraulics - Three hydraulic power packs, one forward for mezzanine decks raised, 2.10m upper mezzanine decks and 3.90m operating anchor winch, capstans and ride control. Two aft for under mezzanine decks. operation of waterjet steering and bucket movement, capstans and Axle loads - 12 tonnes per single axle (European standard) transom ride control. to frame 63/72, 0.8 tonnes per axle forward of frame 63 outboard Ride Control - A ‘Maritime Dynamics’ active ride control system is and 0.8 tonnes on mezzanine decks. fitted to maximise passenger comfort. This system combines, active Fuel Capacity - Six integral aluminium tanks (three in each hull) to trim tabs aft and optional fold-down T-foil located at aft end of provide short and long range capacity. centre bow fitted with active fins. The structural abutment, electrical and hydraulic services to receive the fwd T-foil will be Fresh Water - 5000 litres fitted as standard to the vessel. Construction

Design - Two slender, aluminum hulls connected by a bridging section with center bow structure at fwd end. Each hull is divided Electrical Installations into nine vented, watertight compartments divided by transverse Alternators - A combination of marine diesel driven, brushless, self- bulkheads. Three compartments in each hull prepared as fuel tanks excited alternators (total combined output of 1200kw). with additional strengthening on each of the end bulkheads and Distribution - 415V, 50 Hz 3 phase 4-wire distribution system with intermediate tank top. Welded aluminium construction using neutral earth allowing 240 volt supply, using one phase and one predominantly grade 5383-H116 or 5518-H321, and extrusion grade neutral. Distribution via distribution boards adjacent to or within 6082-T6, 5083-H112, 5383-H112 or 5518-H112. Longitudinal the space they serve. stiffeners supported by transverse web frames and bulkheads.

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STENA HSS 1500

Le type HSS 1500

HSS : High-speed Sea Service

Trois HSS 1500 ont été commandés par la Stena Line aux chantiers finlandais Finnyards en Juillet 1993 au coût unitaire d'environ 65 millions de Livres Sterling. Le premier, le STENA EXPLORER est entré en service au printemps 1996 entre le Pays de Galles et l' Irlande sur un parcours de 55 milles parcouru en 99 minutes.Le second est le STENA VOYAGER et le troisième le STENA DISCOVERY a été livré fin mai 1997 pour la ligne Harwich (UK) - Hook of Holland.

HSS STENA EXPLORER Caractéristiques principales

HSS 1500 Passagers/Véhicules Type Catamaran Ferry DNV +1A1 HSLC R1 Classification Car Ferry A EO ICS NAUT Armateur Stena Rederi Chantiers Finnyards Construction Aluminium et composite Longueur hors-tout 126,6 m

Largeur 40 m

Tirant d'eau 4,5 m

Déplacement 1500 t 2 turbines à gaz LM 2500 soit 2x20500 KW Machines 2 turbines à gaz GE LM1600 soit 2x13500 KW Réducteurs 2 MAAG HPG 185/C Propulseurs 4 WJ KAMEWA S160 4 CUMMINGS-STANFORD de 747 KW Auxiliaires chaque

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25 nds avec 2 LM 1600 soit 27 MW Vitesse 32 nds avec 2 LM 2500 soit 41 MW 40 nds avec les 4 turbines soit 68 MW 8 m3/h avec 2 LM 1600 Consommation 15 m3/h avec 2 LM 2500 50 m3/h avec les 4 turbines Autonomie Capacité GO 235 m3

Capacité Eau douce 20 m3 Passagers 1500 Véhicules 275 ou 120 + 50 camions Equipage 48 à 75 Stabilisation NIL

http://perso.wanadoo.fr/fcapoulade/You@youraddress

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PacifCat On-Board Ramp Feasibility Study

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¾ Technical Memorandum

PacifiCat On-Board Ramp Feasibility Study

August 17, 2000

Performed by:

Jeff Kelton, Sr. Naval Architect John J. McMullen Associates, Inc. 400 Warren Ave., Suite 320 Bremerton, Washington 98337 Tel: (360) 782-1112 Fax: (360) 782-1115

Performed for:

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TECHNICAL MEMORANDUM

From: JJMA – Jeff Kelton, Senior Naval Architect To: PricewaterhouseCoopers - Mr. Mark Hodgson

Subj: PacifiCat On-Board Ramp Feasibility Study

EXECUTIVE SUMMARY

John J. McMullen Associates, Inc., was tasked by PricewaterhouseCoopers to investigate the feasibility of adding vehicle ramps to the existing PacifiCats to facilitate on-board vehicle passage between the upper and lower car decks. The PacifiCats are presently in double-ended operation and dock at two-brow terminals in British Columbia, having the capability of loading vehicles on the two levels simultaneously with two parallel lanes per deck. It is rare to find such two-level terminals anywhere else in the world. Thus this study, while not being a detailed parking or traffic flow study, investigates the feasibility of adding onboard ramps to facilitate the boarding of vehicles on only the lower deck at more conventional ferry terminals.

The study investigated three on-board single-ramp configurations, one for double-ended operation / drive-through loading, one for single-ended operation / bow-to loading, and one for single-ended operation / stern-to loading. Sketches for each of the three configurations confirms the feasibility of the ramps from an arrangement standpoint. An order-of-magnitude estimate of the impacts of the modification upon the ship and the dollar cost thereof are presented in table 1

Table 1: Comparison of Modification Configurations

Configuration Car Capacity Weight (tonne) Terminal Time Performance Costs (US) Double-Ended / Max: 233 Decrease of Small Trim: Negligible Change $1.6M to Drive-Through Real: 228 23.5 - 31 Lengthening Full Load Speed: Appreciable Increase $2.4M Single-Ended / Max: 223 Decrease of Considerable Trim: Positive Change (aft trim) $0.8M to Bow-To Ops Real: 213 39.5 – 54.5 Lengthening Full Load Speed: Significant Increase $1.2M Single-Ended / Max: 230 Decrease of Considerable Trim: Negative Change (fwd trim) $0.8M to Stern-To Ops Real: 220 29 - 44 Lengthening Full Load Speed: Slight Increase $1.2M

Ramp placement was determined to have the least impact on ship systems if located in the lane just to port of ship’s centerline, rather than at the side shell. Having the ramps hoistable preserves the weathertight integrity of the upper deck. Having the ramps as much as possible within the bounds of the weathertight roller doors preserves the existing fire boundaries and the operation of the water fog fire suppression system.

The scantlings of the PacifiCats were painstakingly optimized to the maximum during the design phase, and probably very little margin exists currently on global longitudinal strength. The cutouts in the decks for the ramps will have a very significant deleterious effect on the global strength of these vessels, and will require extensive structural modifications to provide adequate reinforcements. For these reasons, only single-lane ramps, as opposed to double-lane ramps, were investigated. Also, certain pairs of existing stanchions will require removal for adequate

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vehicle turning clearances, and compensating structure designed and installed, to carry the loads the removed stanchions supported.

An extensive 3D finite element engineering analysis will be required to fully prove the feasibility of installing vehicle ramps on the PacifiCats, as well as a detailed design effort to eventually construct them. These costs are reflected in table 1.

BACKGROUND & ORGANIZATION OF REPORT

The three PacifiCats were designed for the specialized two-deck loading terminals of B.C. Ferries at Horseshoe Bay, north of Vancouver, and at Departure Bay, north of Nanaimo on Vancouver Island. Two of the PacifiCats, the Explorer and Discovery, are shown in figure 1 docked bow-to and stern-to at the Departure Bay Terminal.

Figure 1: Departure Bay Terminal

The PacifiCats are presently capable of loading vehicles on two levels simultaneously with two parallel lanes per deck. There is presently no way for vehicles to move between the upper and lower vehicle decks onboard. This configuration requires that the shore facility be equipped with a double-deck vehicle brow. The offloading of passenger cars from the upper deck, and a commercial truck and cars from the lower deck, is shown in figure 2.

Figure 2: Passenger Cars Disembarking Upper Deck / Truck Disembarking Lower Deck

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While such vehicle brows are common in British Columbia, they are not common elsewhere. It is expected that many prospective buyers will be interested in what it would take to modify the ships such that all vehicle loading and unloading is accomplished from the lower vehicle deck.

This memorandum presents the results of John J. McMullen Associates’ brief feasibility study of this subject. The study investigated three on-board ramp configurations, one for double-ended operation / drive-through loading, one for single-ended operation / bow-to loading, and one for single-ended operation / stern-to loading. For each of the three configurations we present sketches of the studied configuration, and order-of-magnitude estimates of the impacts of the modification upon the ship and the dollar cost thereof. All costs are estimated in US Dollars, assuming performance of the work by a North American shipyard. All such cost estimates are necessarily rough, as the variance in price between shipyards in different parts of the world and with different skill levels in aluminum fabrication, can of course be considerable.

RAMP ARRANGEMENT CONSIDERATIONS

Flexible Arrangements: Vehicle ramps aboard ferries, whether fixed or hoistable, are a very mature technology with several ferry-building shipyards worldwide having experience installing them during new construction or as retrofits to add increased flexibility and vessel usefulness. Often such ramps are just one element of on-board vehicle loading systems which may include stern, bow, and/or side loading doors, hoistable mezzanine decks, ramp covers, and flood control doors as shown in figure 3 below.

Figure 3: Flexible Vehicle Loading Systems

The flexibility provided by such vehicle loading systems, and vehicle ramps in particular, can be vitally important to commercial operators with conventional ferry slips which normally would have a single brow transfer span for loading and unloading at the lower vehicle deck level. This flexibility is indispensable for naval sealift applications of the PacifiCats where the loading and offloading of military vehicles must be accomplished, in an efficient manner anywhere in the world where shore-side infrastructure may range from very good at to very primitive.

Ramp Placement: Maximum utility and efficiency would dictate that the present drive-thru double-ended capabilities of the PacifiCats be preserved. This can be accomplished by the installation of two ramps, one in the fore part of the ferry and another in the aft part. If end- hinged, and hoistable, this allows for the full load-out of the lower vehicle deck when the ramps are in the raised position flush with the upper vehicle deck. Backing and filling of vehicles would be required on the upper deck to take full advantage of its available vehicle deck space.

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Single-ended operation of the PacifiCats is also feasible. The accommodation of a single end- hinged hoistable vehicle ramp located at the end of the ferry where the loading/unloading occurs works best in these configurations. Bow loading/unloading, as opposed to the stern would experience easier dock maneuvering, especially in strong wind, as there is greater control with the waterjets in the forward mode than in reverse mode. Both single-ended configurations would experience a significantly greater requirement for the backing and filling of vehicles on the upper deck to maximize that deck’s utilization as compared with double-ended operation, and thus terminal turnaround times will be longer in the case of the single-ended configurations.

Especially in the case of naval sealift applications of the PacifiCats, placement of these ramps near the center of the vessel insures the greatest possibility of continued operation of the ramp if the ship sustains battle damage. In the case of commercial applications, placement of the ramps near the centerline of the ferry minimizes the impacts to existing ship systems as compared to placement of the ramps near the side shell of the ferry where many such systems exist.

In order to maintain the integrity of the PacifCat’s water fog fire suppression system, the ramps should be placed as far as practicable within the boundaries defined by the upper vehicle deck’s fore and aft weathertight roller doors, shown in figure 4. As the sea states in which the ferries may be operated in the future may well exceed those experienced between Nanaimo and Vancouver, it is also important that the weather tightness of the upper vehicle deck exterior to the fore and aft roller doors be maintained.

Forward Roller Doors Aft Roller Doors

Figure 4: Upper Vehicle Deck Weathertight Boundaries

Island structures, which enclose passenger access means to the lounge deck above, exist in the lane on the upper vehicle deck just to starboard of centerline. One such structure is shown in figure 5. The location of these island structures limits how far toward amidships a vehicle ramp may be situated and still have enough turning clearance for vehicles to avoid these enclosures.

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Figure 5: Island Structures

Structure: Numerous stanchions exist on the upper vehicle deck as shown in figure 6. The longitudinal spacing of these stanchions is approximately one car-length, necessitating the removal of one pair of these stanchions at the top of the ramp to provide enough vehicle turning clearance. Compensating structure will need to be added to the adjacent remaining stanchions, and to the overhead, to carry the loads that the removed pair of stanchions supported.

Figure 6: Upper Deck Stanchions

This stanchion removal and compensating structure replacement process may also be required elsewhere on the upper vehicle deck, especially in the case of single-ended ferry operations where a stanchion pair would inhibit the turning of cars to face in the direction in which unloading would occur.

The structural design of the PacifiCats was optimized for lightest scantlings to achieve the best balance among operational requirements, weight, powering and running costs. Complex 3D finite element analyses were performed to achieve these light optimized scantlings. Various load case stresses were investigated including the wave crest landing case shown in figure 7. Because of the overall slender length-to-beam proportions of the PacifiCats dictated by B.C. Ferries’ terminal requirements, longitudinal and global strength considerations were uppermost in the structural design of the vessels. Deck penetrations such for the elevator, stairways, hatches, ventilation, and exhaust, were minimized as much as possible. It is clear that to provide cutouts in the upper vehicle deck that are the equivalent of more than 5 standard cars in length and 1 car in breadth will have a profound negative effect on the global strength of the vessel. Fortunately, the cutouts will occur near the neutral axis of the box girder, not close to the tunnel top or the superstructure support deck (raft deck in the midship section shown in figure 8) where the most extreme stresses occur. Corner stresses in the deck cutouts will be high necessitating significant doubler plate deck reinforcing. Major structural reinforcement will be required to recover the longitudinal strength lost to the cutouts. Further 3D finite element analyses will be

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required to properly design the modifying structure, especially where the vessel may be operated in sea states with more than a 2.5m significant wave height, which was one of the governing criteria in the design of the PacifiCats.

Figure 7: Wave Crest Landing Structural Stresses

Figure 8: Midship Section With Ramp

THE ‘AS-IS’ CONFIGURATION

Shown below in figure 9 is the vehicle arrangement of the PacifiCats as they exist presently. The 250 vehicle capacity is comprised of 133 vehicles on the lower deck and 117 vehicle on the upper deck. This ‘As-Is’ configuration serves as the starting point in the planning of all other possible ramp-incorporating arrangements.

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Upper Deck – 117 Vehicles

Lower Deck – 133 Vehicles

Figure 9: PacifiCat ‘As Is’ Configuration - 250 Vehicles Total

Interesting features to note in this ‘As-Is’ configuration are the following:

Although being an efficient double-ended drive-through arrangement, some backing and filling of cars is still required to fully load out the two vehicle decks.

On the lower deck to a certain degree, but on the upper deck to a much greater degree all cars are loaded as far aft as possible to maintain the most optimal vessel trim condition for the highest service speeds.

On the upper deck, vehicles are shown underneath the aft roller doors. In actual operation, these roller doors would be closed so that the water fog fire suppression system could function properly. Thus, either 6 fewer cars would be carried, or a more forward placement of all cars forward of the aft roller doors would need to occur (with a slightly less favorable trim condition) if the full 117 vehicle capacity was to be maintained.

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FIRST CONFIGURATION - DOUBLE-ENDED/DRIVE-THROUGH LOADING

Arrangement and General Description: The PacifiCats, as presently configured, use a double- ended / drive-through loading scheme, where vehicles drive aboard the ship over one end, and drive off the ship at the other end. This is an efficient loading scheme, which results in the fastest possible terminal turn-around times, since there is very little maneuvering of vehicles required. To accomplish double-ended drive-through loading using on-board ramps requires at least two ramps. Such a configuration, with maximum load-out is depicted in figure 11. In a stern-to docking scenario, vehicles boarding the ship over the stern will drive up the aftbody ramp onto the upper vehicle deck. They will park as also depicted in figure 11. Note that in order to fill in the parking some backing of vehicles will be necessary, as is presently the case.

Disembarking of vehicles is the reverse of loading, starting with the vehicles at the stern. These vehicles will drive down the forebody ramp and ashore. After the stern end of the upper deck is empty, then the vehicles toward the bow can back up, and proceed down the forebody ramp themselves.

In this system the ramps are hoistable. Once the upper deck is loaded the ramp is hoisted up until it is flush with the upper deck. This clears access to all lanes of the lower deck. Note that in this scheme the lower deck does not require any backing or maneuvering, which means that the loading of large vehicles such as trucks or coaches is not unduly complicated. Further, since the depicted concept only uses a portion of the available width for ramps, it would be possible to have cars loading on the lower deck via the outermost lanes, while vehicles arriving in the center lanes are moving to the upper deck. This should help minimize the impact upon turn-around time.

This configuration is only one of myriad possible ramp configurations. Other possible configurations may be preferred due to some operator's particular needs and / or expected vehicle mix. This configuration, however, will be generally typical in cost and impact of any other ramp arrangement.

Ship Impacts: Having the ramps located in the lane just to port of centerline minimizes impacts to ship systems, which would not be the case if the ramps were near the side-shell with its many ventilation and exhaust ducts, as shown in figure 10.

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Figure 10: Side-Shell Systems

Near centerline and under the upper deck, there may be some impacts to lighting, electrical wireways, firefighting and other fluid piping systems, but these should be readily reroutable. As noted in a previous section of this study the structural impacts will be considerable. Restoration of the structural fire protection in impacted areas will also be required. Electrical and hydraulic requirements of ramp systems should not significantly burden the vessels existing distributive system capacities.

Vehicle Capacity: The direct footprint of the ramp is approximately 5 AEQ on the upper deck for a ramp with a slope of 1:6 (which prevents vehicles from ‘bottoming-out’). This assumes that no vehicles park on the ramp, but that they do park under the ramp when the ramp is in the raised position. An athwartships clear buffer zone on the upper deck of 1 car-length near amidships will be necessary to allow for adequate vehicle turning clearances when disembarking. Figure 11 shows that the upper deck will accommodate a maximum of 100 vehicles. The maximum lower deck capacity should remain unchanged at 133 vehicles.

In the proposed configuration, therefore, the ship will have 2 ramps and a maximum capacity of 233 vehicles. A more realistic loading capacity for minimum terminal turnaround times may be 5 fewer AEQ, or 228 vehicles total.

Thus the overall effect of adding two ramps is a weight reduction of approximately 23.5 to 31 tonnes. As the ramps are well distributed fore and aft, the trim of the vessel should not be significantly affected either fore or aft, from what it is presently.

Terminal Turn-Around Time: The two-ramp drive-through configuration will have small negative impact on the present loading and unloading times due to an increase in backing and

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filling required. B. C. Ferries determined that the best practice for loading of the PacifiCats is to flood the upper deck first, loading the lower deck more slowly. Once the upper deck was full, then load "fine tuning" is accomplished via the latter phases of loading on the lower deck. This same scheme will apply when the ramps are fitted. The ramps will require that the upper deck be loaded first and unloaded last, because lowering the ramps for access requires that the lower deck be clear. Note that there is some degree of simultaneous loading that is still possible, since the ramps do not block all of the loading lanes. Thus, while one line of traffic rolls to the upper deck, other lines may be loading outboard on the lower deck.

In consideration of all of the above facts, it is expected that the addition of two ramps on order to preserve the drive-through feature of the PacifiCats, will have a small negative impact on the present load and unload times.

Performance: Because of the likely weight impact of a reduction of 23.5 to 31 tonnes, combined with a negligible effect on trim, there will be an appreciable increase in performance in the full load condition. It may be worth noting that the weight impact is negligible upon light ship weight. This means that performance in the light condition will not be changed significantly. This, in turn, suggests that the range of performance between full and empty will be increased appreciably once the ramps are fitted.

Cost Estimate: The unit cost per hoistable vehicle ramp, without structural reinforcement included, is likely to be between $0.4 and $0.6M (US). With structural reinforcement modifications included, the cost per ramp would likely be between $0.8M and $1.2M (US). Therefore, the total cost of this configuration is estimated to be between $1.6M and $2.4M (US). Costs are based on the assumption of the work being performed by a North American shipyard. The cost estimate is necessarily rough, as the variance between shipyards in different parts of the world and with different skill levels in aluminum fabrication, can be considerable.

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Upper Deck – 100 Vehicles

Lower Deck – 133 Vehicles

Figure 11: PacifiCat Double-Ended / Drive-Through Configuration – 233 Vehicles

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SECOND CONFIGURATION – SINGLE ENDED/BOW-TO LOADING

Arrangement and General Description: For operators which require single-ended operation, the PacifiCats will lend themselves better to docking bow-to, as maneuverability is greater in the forward direction, especially in strong winds. To accomplish single-ended bow-to loading and unloading, one ramp is required in the forebody. Such a configuration, with maximum load-out is depicted in figure 12. Vehicles boarding the ship over the bow will drive up the ramp onto the upper deck, execute a u-turn and park facing the bow. Backing and filling of vehicles will be necessary - much more so than in a drive-through configuration. Disembarking of vehicles is the reverse of loading, starting with the vehicles at the stern. These vehicles will drive down the forebody ramp and ashore, with the vehicles toward the bow backing up and then proceeding down the forebody ramp themselves.

Once the upper deck is loaded, the ramp is hoisted up until it is flush with the upper deck, clearing access to all lanes of the lower deck. Note that in this scheme the lower deck also requires u-turns and backing, which means that the loading of large vehicles such as trucks or coaches is more complicated. It is possible to have cars loading on the lower deck via the outermost lanes, while vehicles are moving to the upper deck, helping to somewhat minimize the impact upon terminal turn-around times.

Ship Impacts: Impacts to structure will be considerable, but impacts to lighting, electrical wireways, piping, and other ship distributive systems will be minimal as these should be readily re-routable in the affected area.

Vehicle Capacity: An impact of 5 AEQ will be felt on the total vehicle capacity on the upper deck for the ramp itself, plus approximately 6 more for space utilization inefficiencies on the lower deck. In addition, it will not be possible to fully load-out the lane that contains the ramp. An athwartships clear buffer zone on the upper deck of 1 car-length near amidships will be necessary to allow for adequate vehicle turning clearances when disembarking. Figure 12 shows that the upper deck will accommodate a maximum of 96 vehicles. The maximum lower deck capacity, with impacts accounted for, is 127 vehicles.

Therefore, in the proposed configuration, the ship will have a maximum capacity of 223 vehicles. A more realistic loading capacity for minimum terminal turnaround times may be 10 fewer AEQ, or 213 vehicles total.

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effect of adding the ramp is a weight reduction of approximately 39.5 to 54.5 tonnes. There will be a net decrease in weight forward, which increases the trim aft slightly, which is a beneficial effect for vessel speed.

Terminal Turn-Around Time: Loading will proceed by flooding the upper deck first with cars, while loading the lower deck more slowly, followed by “fine tuning” on the lower deck in the latter stages. Some degree of simultaneous loading will still be possible since the ramp blocks only one loading lane of the lower deck. Added terminal time will be required for the u-turns and the backing and filling on both decks. Terminal turn-around time is significantly increased primarily due to the nature of single-ended operations – not the presence of the ramp.

Performance: Because of the net decrease in weight of 39.5 to 54.5 tonnes, combined with a more favorable aft trim in the full load condition, there will be a significant increase in performance. Light ship performance should be close to what it is presently.

Cost Estimate: The total cost of this configuration is estimated to be between $0.8M and $1.2M (US). Costs are based on the assumption of the work being performed by a North American shipyard.

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Upper Deck – 96 Vehicles

Lower Deck – 127 Vehicles

Figure 12: PacifiCat Single-Ended / Bow-To Loading Configuration – 223 Vehicles

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THIRD CONFIGURATION - SINGLE-ENDED/STERN-TO LOADING

Arrangement and General Description: For operators which require single-ended operations with stern-to docking, one ramp is required in the aftbody. Such a configuration, with maximum load-out, is depicted in figure 13. Vehicles boarding the ship over the stern will drive up the ramp onto the upper deck, execute a u-turn, and park facing the stern. Backing and filling of vehicles will be necessary - much more so than in a drive-through configuration. Disembarking of vehicles is the reverse of loading, starting with the vehicles at the stern. These vehicles will drive down the forebody ramp and ashore, with the vehicles toward the bow backing up and then proceeding down the forebody ramp themselves.

Vehicle Capacity: An impact of 5 AEQ will be felt on the total vehicle capacity on the upper deck for the ramp itself, plus approximately 6 more for space utilization inefficiencies on the lower deck due to having to turn vehicles. In addition, it will not be possible to fully load-out the lane that contains the ramp. An athwartships clear buffer zone on the upper deck of 1 car-length near amidships will be necessary to allow for adequate vehicle turning clearances when disembarking. Figure 13 shows that the upper deck will accommodate a maximum of 103 vehicles. The lower deck capacity, with impacts accounted for, is 127 vehicles. Therefore, in the proposed configuration, the ship will have a maximum capacity of 230 vehicles. A more realistic loading capacity for minimum turnaround times may be 10 fewer AEQ, or 220 vehicles total.

Weight: The net weight increase of the ramps themselves is minimal, if constructed out of aluminum. Each ramp should weigh approximately 2.5 tonnes, but will replace existing deck structure of about 2 tonnes. With structural reinforcement added in, the net increase in weight due to one ramp will be approximately 1 tonne. Note that the weight of 20 to 30 fewer AEQ, as compared with the vessel’s current configuration, is about 30 to 45 tonnes. Thus the overall effect of adding the ramp is a weight reduction of approximately 29 to 44 tonnes. There will be a net decrease in weight aft, which will increase the trim forward slightly - a non-beneficial effect for vessel speed.

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Performance: Because the benefit of a net decrease in weight of 29 to 44 tonnes, may be offset somewhat by a less favorable forward trim in the full load condition, there will be a slight increase in performance. Light ship performance should be close to what it is presently.

Cost Estimate: The total cost of this configuration is estimated to be between $0.8M and $1.2M (US). Costs are based on the assumption of the work being performed by a North American shipyard.

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Upper Deck – 103 Vehicles

Lower Deck – 127 Vehicles

Figure 13: PacifiCat Single-Ended / Stern-To Loading Configuration – 230 Vehicles

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CONCLUSIONS AND RECOMMENDATIONS

Installing on-board ramps from an arrangement standpoint has been shown by this study to be feasible. Any ramp configuration must maintain the integrity of the superstructure’s fire protection systems, and allow for vessel operations in higher sea states. Hoistable end-hinged ramps, as opposed to fixed ramps are best for maintaining this integrity.

Clearly, any on-board ramp configuration has a significant cost, both in terms of initial dollar outlay and in terms of revenue impact due to car spaces lost. It will also increase the turn-around time of the ship. Whether such costs are acceptable will depend upon the owner's intended route and service. Offsetting these impacts to some degree however, is the advantage of an increase in full load performance due to the decrease in full load displacement caused by the lost car spaces.

For minimum terminal turnaround times, double-ended operation with two hoistable ramps is the best option. Operational savings will clearly offset the increased capital costs of the conversion work. For operators that choose single-ended operations with one hoistable ramp, bow-to loading has advantages over stern-to loading with regard to vessel maneuverability, optimum trim conditions, powering, and speed.

Installing on-board ramps from a strength standpoint has not yet been shown to be feasible by this study due to its limited scope. Further extensive 3D finite element analyses to properly design the compensating structure are recommended in concert with Incat Designs Sydney (the designers of the PacifiCats) and Det Norske Veritas (the classification society). Coordination with Robert Allan Ltd. (the systems designers) is recommended to re-route and re-design impacted ship systems.

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APPENDIX C.

VEHICLE FOOTPRINT DATA

C-1

Figure C-1

C-2

Figure C-2

C-3

Figure C-3

C-4

Figure C-4

C-5

Figure C-5

C-6

M927, Truck Extended Bed, 7 ton 16R20 radial tires (6)

High Mobility Multipurpose Wheeled Vehicle (HMMWV) – Typical – 4 tires, 37 x 12.5R-16.5

C-7

M101A1 – Trailer, 2 tires unknown size

155MM Howitzer – 8 tires, large but size is unknown.

Note: This howitzer is reported to have a weight of 5765 pounds. The 9000 pound howitzer specified in the military vehicle payload for the conversion is only shown with two tires but additional anchoring/bracing locations. Additional work is underway to determine the appropriate characteristics of the howitzer to be included in the loadout.

C-8

Medium Tactical Vehicle Replacement (MTVR) – Replaces M923, M925, M927 and M928 – All tires are 16R20’s, single radial tire on each axle

Standard Wheel Base Extended Wheel Base

M923A1M927A1 MK23 Std Cargo MK27 XLWB Cargo Cross- * Cross- * Cross- * Cross- Loaded condition Empty country Highway Empty country Highway Empty country Highway Empty country * Highway Gross Weight (lbs) 21740 31740 42740 26135 36135 46135 27882 42650 58361 30195 44666 60466 #1 Axle Weight (lbs) 9275 9740 10000 N/A 11735 N/A 12640 12665 12433 13358 13342 13147 #2 Axle Weight (lbs) 6232 11000 16370 N/A 12200 N/A 8473 14951 21902 9161 15695 22808 #3 Axle Weight (lbs) 6232 11000 16370 N/A 12200 N/A 6763 14945 24026 7676 15692 24511 Maximum Height (in) 122.3 122.3 122.3 N/A 120.6 N/A 142.1 140 139.2 141.1 139.4 139 Reduced Height (in) 93.9 93.9 93.9 N/A 93.5 N/A 99.1 99 99.1 98.4 98.3 99.4 CG from Front (in) N/A N/A N/A N/A N/A N/A 98.8 129.3 145.8 119.1 151.4 169.8 CG from Ground (in) N/A N/A N/A N/A N/A N/A 39.7 53.8 60.6 38.8 52.8 59.6 Max Tire Press (psi)* 80 60 80 80 60 80 47 35 96 47 35 96 Notes: N/A (Not Available) * Highway Loads for MTVR provided for information only. Since the only load that consistently gets the vehicle up to its full rated 15 tons is ammunition, it is very unlikely a vehicle would be mobile loaded at 15 tons aboard ship. ** Tire pressure would be set for the appropriate load and terrain. Aboard ship it would nomiN/Ally be set at cross country (or the lower sand, mud & snow) setting to match an over the beach load (7.1T) and the terrain expected on the beach. Highway psi

C-9

MK-48 Logistics Vehicle System (LVS), Front Power Unit

This photograph shows the front power unit with a trailer. The military vehicle payload includes the front power unit only. All four tires are 16R21 radials.

C-10

Rough Terrain Container Handler (RTCH) – Not included in the MEU Loadout for Conversion Vessel. Presented for information and to demonstrate large tire footprints that various vehicles may have.

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PROJECT TECHNICAL COMMITTEE MEMBERS

The following persons were members of the committee that represented the Ship Structure Committee to the Contractor as resident subject matter experts. As such they performed technical review of the initial proposals to select the contractor, advised the contractor in cognizant matters pertaining to the contract of which the agencies were aware, performed technical review of the work in progress and edited the final report.

Chairman

Members Contracting Officer’s Technical Representative:

Marine Board Liaison:

Executive Director Ship Structure Committee:

SHIP STRUCTURE COMMITTEE PARTNERS AND LIAISON MEMBERS

PARTNERS The Society of Naval Architects and Marine The Gulf Coast Region Maritime Engineers Technology Center

Mr. Bruce S. Rosenblatt Dr. John Crisp President, Executive Director, Society of Naval Architects and Marine Engineers Gulf Coast Maritime Technology Center

Dr. John Daidola Dr. Bill Vorus Chairman, Site Director, SNAME Technical & Research Steering Gulf Coast Maritime Technology Center Committee

LIAISON MEMBERS American Iron and Steel Institute Mr. Alexander Wilson American Society for Testing & Materials Captain Charles Piersall (Ret.) American Society of Naval Engineers Captain Dennis K. Kruse (USN Ret.) American Welding Society Mr. Richard Frank Bethlehem Steel Corporation Dr. Harold Reemsnyder Canada Ctr for Minerals & Energy Technology Dr. William R. Tyson Colorado School of Mines Dr. Stephen Liu Edison Welding Institute Mr. Dave Edmonds International Maritime Organization Mr. Tom Allen Int’l Ship and Offshore Structure Congress Dr. Alaa Mansour INTERTANKO Mr. Dragos Rauta Massachusetts Institute of Technology Mr. Dave Burke / Captain Chip McCord Memorial University of Newfoundland Dr. M. R. Haddara National Cargo Bureau Captain Jim McNamara Office of Naval Research Dr. Yapa Rajapaksie Oil Companies International Maritime Forum Mr. Phillip Murphy Tanker Structure Cooperative Forum Mr. Rong Huang Technical University of Nova Scotia Dr. C. Hsiung United States Coast Guard Academy Commander Kurt Colella United States Merchant Marine Academy Dr. C. B. Kim United States Naval Academy Dr. Ramswar Bhattacharyya University of British Columbia Dr. S. Calisal University of California Berkeley Dr. Robert Bea University of Houston - Composites Eng & Appl. Dr. Jerry Williams University of Maryland Dr. Bilal Ayyub University of Michigan Dr. Michael Bernitsas University of Waterloo Dr. J. Roorda Virginia Polytechnic and State Institute Dr. Alan Brown Webb Institute Dr. Kirsi Tikka Welding Research Council Dr. Martin Prager Worchester Polytechnic Institute Dr. Nick Dembsey World Maritime Consulting, INC VADM Gene Henn, USCG Ret. Samsung Heavy Industries, Inc. Dr. Satish Kumar RECENT SHIP STRUCTURE COMMITTEE PUBLICATIONS

Ship Structure Committee Publications on the Web - All reports from SSC 392 and forward are available to be downloaded from the Ship Structure Committee Web Site at URL: http://www.shipstructure.org SSC 391 and below are available on the SSC CD-ROM Library. Visit the National Technical Information Service (NTIS) Web Site for ordering information at URL: http://www.ntis.gov/fcpc/cpn7833.htm

SSC Report Number Report Bibliography

SSC 437 Modeling Longitudinal Damage in Ship Collisions A.J. Brown, JAW Sajdak 2005

SSC 436 Effect of Fabrication Tolerances on Fatigue Life of Welded Joints A. Kendrick, B. Ayyub, I. Assakkaf 2005

SSC 435 Predicting Stable Fatigue Crack Propagation in Stiffened Panels R.J. Dexter, H.N. Mahmoud 2004

SSC 434 Predicting Motion and Structural Loads in Stranded Ships Phase 1 A.J. Brown, M. Simbulan, J. McQuillan, M. Gutierrez 2004

SSC 433 Interactive Buckling Testing of Stiffened Steel Plate Panels Q. Chen, R.S. Hanson, G.Y. Grondin 2004

SSC 432 Adaptation of Commercial Structural Criteria to Military Needs R.Vara, C.M. Potter, R.A. Sielski, J.P. Sikora, L.R. Hill, J.C. Adamchak, D.P. Kihl, J. Hebert, R.I. Basu, L. Ferreiro, J. Watts, P.D. Herrington 2003

SSC 431 Retention of Weld Metal Properties and Prevention of Hydrogen Cracking R.J. Wong 2003

SSC 430 Fracture Toughness of a Ship Structure A.Dinovitzer, N. Pussegoda, 2003

SSC 429 Rapid Stress Intensity Factor Solution Estimation for Ship Structures Applications L. Blair Carroll, S. Tiku, A.S. Dinovitzer 2003

SSC 428 In-Service Non-Destructive Evaluation of Fatigue and Fracture Properties for Ship Structure S. Tiku 2003

SSC 427 Life Expectancy Assessment of Ship Structures A. Dinovitzer 2003

SSC 426 Post Yield Stability of Framing J. DesRochers, C. Pothier, E. Crocker 2003